President Anwar Sadat, who committed himself yesterday to making a solitary voyage into the uncharted waters of peace with Israel, has now turned his attention to explaining the decision to the Egyptian people and trying to persuade other Arab leaders to accept it.

Rather than celebrate or claim a triumph, Sadat has retired from public view without a word, which explains why the Cairo press has been restrained in commentary about the final agreement on a treaty with Israel that Sadat reached in yesterday's long meeting with President Carter, and why public response here has been muted.

Egyptian Prime Minister Mustafa Khalil said today, nevertheless, that Sadat is preparing to fly to Washington March 22 or 23 on the assumption that Israel will have given final approval to the treaty and that it will be ready for signing.

The Egyptian president has little to fear among his own people, who have massively supported his quest for peace. But he is more isolated than ever among other Arabs, who are unwilling or unable to follow where he is leading, and he already has begun what his aides admit is the Herculean task of defusing their anger.

The Palestine Liberation Organization, predictably, urged Arab oil countries to cut off their aid to Egypt and denounced the accord as a plot to frustrate the Palestinian struggle for nationhood. Syria's official radio joined the PLO condemnation, calling the accord a "conspiracy" and denouncing Sadat for making "humilitating" concessions to Israel.

It is questionable whether other Arab nations actually can do Sadat or Egypt any material damage, but Egypt's spiritual separation from the Arab mainstream already has become a source of deep anxiety among many people here.

Sadat was at Carter's said at the airport when the American president delivered his surprising statement yesterday that a treaty was at last within reach. But as soon as Carter boarded his plane, Sadat uncharacteristically turned away from waiting reporters and television cameras and flew off in a helicopter. He has said nothing since, and apparently is not going to for several days.

He even refused today to see correspondents of American television networks, a sure sign that he is hibernating to plan his next move.

On Satruday, he will address members of the People's Assembly, or parliament, who belong to his National Democratic Party. He is to give them what is officially described as " a full and accurate picture" of how the treaty agreement was reached.

By then Khalil will have briefed the Cabinet, which, unlike its Israeli counterpart, is entirely under Sadat's thumb and will probably do as it is told.

There has been strong criticism of Sadat's peace policies from a handful of dissidents in parliament, but it is not here at home that Sadat can expect to encounter any significant opposition. It is in the other Arab countries, many of which have denounced him as a traitor and a sellout since he first wnet to Jerusalem 16 months ago.

Contrary to his own predictions, the other Arabs have not fallen into line. Now that he has committed himself to a treaty that contains less in the way of Israeli withdrawal and Palestinian rights than he demanded when he went to Israel, the inevitable new chorus of outrage has begun to be hears.

In an attempt to diminish its impact, Sadat has begun diplomatic initiative toward most of the other Arab countries. It bagan today with a trip by Vice President Hosni Mobarak to Sudan, the Arab state most closely aligned with Egypt and a firm supporter of Sadat's policy

Messages of explanation, and perhaps special emissaries, also will be sent to most other Arab capitals. The exceptions are the five members of the Steadfastness Froint of opposition to Sadat -- Syria, Libya, South Yemen, Iraq and Algeria -- and Kuwait, with which Egyptian relations are at a nadir since the Kuwaitis denounced Sadat and reduced economic aid last year.

Some of the countries Sadat is approaching, such as Morocco, Oman and North Yemen, are likely to give him at least tepid support. But the general picture of Egyptian relations with the rest of the Arabs is grim.

"It is a problem for us," Deputy Foreign Minister Boutros Ghali acknowledged today. "These messages are only the beginning of a long process of trying to overcome their emotional reaction and their difficulties of comprehension."

Egypt's objective, he said, is a kind of "political education" of the other Arabs, in which Egypt will argue that negotiations with Israel produce more than threats and slogans and will try to emphasize what it has accomplished so far.

If the other Arabs reject these arguments, as is probable at least for many months, they face the question of what they can do to show their opposition.

The Steadfastness states already have broken diplomatic relations with Egypt. Jordan has delivered its heaviest blow in the form of a refusal to participate in the negotiations. Syria and Iraq have patched up their own quarrel to join forces against Sadat -- all without derailing him.

At the Baghdad summit conference last November, all the Arab states joined in condemining the Camp David agreements and decided to impose economic sanctions on Egypt if Sadat went ahead with a treaty. Iraq has now asked for an Arab foreign ministers' meeting to put those sanctions into effect.

That leaves the key country -- Saudi Arabia. The Saudis joined the others in the Baghdad resolutions and SaudiEgyptian relations have been cool ever since. But the Saudis only last month went ahead with a commitment to provide about half a billion dollars to finance Egypt's purchase of American combat jets and also have kept up their contracts for joint arms manufacturing.

Moreover, according to authoritative reports, Egypt recently has improved its balance of payments picture and substantially lessened its dependence of Riyadh, and the Saudis have less economic sway over Sadat than is widely supposed.

But what Sadat wants more than money from Saudi Arabia is political support, an endorsement of what he is doing that would bring Jordan and the PLO into the peace negotiations. There is no reason to believe he has any chance of obtaining that, but if he does not he is clearly prepared to go ahead without it.