Carter administration insiders sought yesterday to calm "semi-hysteria" in official Washington over last week's Cabinet shakeup, but one of them, Robert S. Strauss, conceded that President Carter "would have been better off" had it been done differently.

As the president turned his attention to the search for replacements for three top jobs left vacant in last week's purge, press secretary Jody Powell said "the semi-hysteria here in Washington" was not shared west of the Potomac.

Strauss, Carter's Middle East trouble-shooter and domestic political adviser, spread the same message at breakfast with reporters. At a weekend lunch with friends in Dallas, Strauss said, the only reference to the shakeup was the question: "Who's Brock Adams?"

Adams is the ousted secretary of transportation, one of three top posts for which Carter is seeking permanent replacements. Powell said top priority is being given to a successor for G. William Miller, who is leaving the chair of the Federal Reserve Board to replace W. Michael Blumenthal as secretary of the Treasury. The third vacant post is secretary of housing and urban development, which Patricia R. Harris is leaving to succeed Joseph A. Califano Jr. at the Health, Education and Welfare Department.

Strauss defended the shakeup as necessary, but conceded it was "a messy business . . . debilitating at best."

As for the mass resignation offer by the Cabinet and senior White House staff that preceded the firings, Strauss said Carter "would have been better off if it had not been done," but said the impact of the gesture had not been foreseen by anyone. "Obviously, the Cabinet resignation did not sit well. Maybe it was a failure of articulation or explanation," Strauss said.

But, like Powell and White House chief of staff Hamilton Jordan, who did another of his series of television interviews yesterday, Strauss insisted that the furor was local to Washington and temporary in impact.

"Five or six months from now," he said, "the American people will little note nor long remember what happened in the last five or six days."

As for the enhanced role of Jordan, Strauss made two observations: "I think he is uniquely qualified to serve this president," and, "I think he has a serious credibility problem."

Strauss, who has at times tried to serve as a mentor to Jordan, described himself as "highly prejudiced in his behalf." He said the 34-year-old Georgian's greatest asset is that "no one will be able to sell the president off Ham Jordan."

His credibility problem, Strauss said, is centered among "people who do not know him" well, and has two causes: past failure to fulfill the "administrative responsibilities" of his job, including returning phone calls, and widespread publicity about his social escapades. "But he is a mature person now," Strauss said. CAPTION:

Picture, ROBERT S. STRAUSS . . ."a messy business . . . debilitating"