Back in her Capital Hilton suite, she kicks off her high heels, wine-coloured and open-toed, and sinks slowly, softly into an armchair, the elegantly molded head. the black - fringed lids, sagging and drooping in unison with all the rest of her.

Miss Universe had had it today.

They think you're a public servant," she says, but she does not sigh, Janelle Penny Commissiong will not allow herself the simple luxury of a sigh, not now that she has all the more intricate luxuries: the $40,000 cash prize that includes a movie con - tract, the clothes, the limousines at her command , the first-class suites, the adulation . . .

And yet - now she repeats it, "The think you're a public servant. I wonder why. That's not fair. It's not fair. I wasn't running for anything."

She is reminded that is precisely what she did back in July when she competed as Miss Tfinidad and Tobago.

"Oh all right. So I was voted Miss Univeres. THE MOST BEALTIFUL GIRL IN THE WORLD." The voice soft and faintly musical, mocks the title, for she knows she is not that, and says it often.In fact she wants other women to know that you don't have to be "5 feet 8 and so perfect. Just so perfect." to win. She is 5 - feet - five.

But at 24, she is very pretty in a wholesome, almost cherubic sort of way, and she has a set of winged eye brows that take flight whenever she is amused or appalled. And since right now a bit of craziness since her victory. the look she sends is almost. But not quite, beautiful.

"I mean," she says, "I wasn't getting votes from the entire country or world. But now I'm like Carter. Some times I think about that. Some or the people, they act like.I won't vote for you next year."

She breaks up laughing. "They pull graphs in front of you during lunch and they push and they shove autographs in front of you during lunch. Rudeness in a way. But I guess it's part of the territory. Once - right after I did the Mike Douglas show, iran sine. It was pouring outside.

"And this lady . . . This lady wants me to sign an autograph in the rain! And when I rushed inside the limousine, she says, "And you call yourself Miss Universe."

"I could have been dying - and she wouldn't have cared. And I know - I know that next year she'll be standing out there, looking for Miss Universe 1978. And that she won't careless about Miss Universe 1977."

She shrugs lightly. "Some people - they get a kick out of it because I'm Miss Universe. It's not going to hurt to play along with it."

And does she - does Miss Universe 1977 - think it's a big deal to be Miss Universe 1977?

"Do I?" she echoes so loudly, you think she's offended. "DO I?" There is a long tremulous pause. Finally "If I were white, I wouldn't feel it's a big deal. Because they've already had 25 Miss Universe. But it's a big deal because I'm a black woman."

She is the first black Miss Universe. But it is not that alone that makes her different. Janelle Commissiong is a very new kind of beauty contest winner. So much so that you wonder that she survived all the casual absurdities that attend these competitions, that accompany the strutting in the bathing suit. She couldn't careless about the bathing suit. Like pushy autograph hounds, it is of no consequence. She knows what she wants, and it is not glamor.

This - the whole intriguing circus of winning and reigning and posing and smiling that curios complaint smile she flashes - is, all of it, strictly business. She says she will go back to Trinidad when it's over.

"I look at it as a job," she says simply. "And I look at what I'll get out of it by the end of the year. The contacts, the ability to sort of set your career. If I haven't been able to do it by then, then it will have been a waste of time."

And so now it's 40 countries to be visited in one year.And it's NAACP functions until 2 a.m. And this past Saturday it was a 1:30 luncheon, thrown by the wife of the ambassador from Trinidad and Tobago. And interviews. And midnight dances. And no - absolutely no - social life, because she's exhausted by the end of it. Just plain exhausted. And she doesn't smile and say it's all divine. She is something apart from her predecessors. But then, that's partly a function of her background, which is also different.

She's from Trinidad, but lived for 10 years in New York, and that - the combination and confrontation of two disparate cultures - has worked its effect on her. Her parents (now divorced) were separated "for as long as I can remember," and so for 10 of her early years she was brought up by her Aunt June in Trinidad of whom she says, "I see heras my mother."

Her mother brought her to New York, when the girl was 13 "I had no choice in the matter," is how she now puts it). In New York she attended the Fashion Institute of Technology, where she majored in merchandising, while simultaneously becoming, at 20, the youngest buyer in the country for a department store.

"I was surviving in New York," she says simply, "I was working in the humdrum career world. I was doing this and that.But I never felt a part of it. I never felt American."

And so - it was just a year-and-a-half ago - she went back to Trinidad to start a boutique business. And she decided to enter the Miss Trinidad contest to promote her luture dress shop. A lot of her friends advised her against it. In her native contest, she says, "the girls get nothing (gor winning). Not even flowers."

She says this all very matter-of-factly, for it did, after all, get her where she wanted to go.After becoming Miss Trinidad and Tabago. she went on to the Miss Universe contest in Santo Dominago. She had even figured out the odds.

"Honestly," she says, "I thought I would have a better chance (than most). There were 80 girls of which 13 were black. And out of those 18, it was easier to notice me. If anything, (being black) was a plus."

But she also says that a lot of the photographers avoided shooting the black contestants. "And when they were asked why, they said it was because they can't sell our pictures as easily. Most of us come from small Caribbean islands, and so there was (less of a market) for our photographs.

"I won Miss Photogenic," a short, dry laugh. "Which to me was more of a surprise than winning Miss Universe. And this was only because I was photographed the most out of all the black girls. But that doesn't mean I was photographed as much as the average white girl."

She pulls on a cigarette and leans back. "I look at what happened to me as one of the greatest opportunities in life. For me, at least. I don't feel I am - what is the word?"

Her chaperone, a pretty Israeli named Shana obliges. "A sex object," she says helpfully.

"Right. A sex object I don't feel I am that. The man that would look on me as a sex object. I think he thinks of women in general as sex objects.

"Like I said. I know I'm not the most beautiful girl in the world. I happened to be the best overrall in the contest and I'm pleased with the way I look.

But there's nothing to be vain about."

There is something rather awe-in-spiring about watching Miss Universe at the hairdresser's.

"Set my hair back," she advises Rene Fontaine at the Capital Hilton. Not too much teasing, she adds, laconically.For the best of the session she plunges indifferently into a series of fashion magazines and does not even glance at the mirror.

Once she looks up, but it's to tell Rene that one of his fashion magazines is (despite his protests to the contrary) pretty out of date. "I think you have a collector's item here," she grins mischievously up at him. She is looking for a dress. Something soft, something clingy. Not boots - "My feet perspire."

"The Most Beautiful Girl in the World," sings Rene, as he comos out the set. And now - for the first and last time - Miss Universe gazes into the mirror. But it is as if she were appraising a stranger. She is asked if she's ever acted before.

"All my life," she tells her reflection. Then she smiles. "The whole world's a stage, they say."

"Touche," says Rene.