Secretary of State George P. Shultz and national security affairs adviser Robert C. McFarlane flew to Geneva in an Air Force plane last night for U.S.-Soviet talks aimed at restarting arms control negotiations between the nuclear superpowers.

An unusually large U.S. official party arrived in Geneva this morning, about eight hours before the arrival from Moscow of Soviet Foreign Minister Andrei A. Gromyko and his aides. Two days of talks are scheduled to begin Monday morning.

White House officials said McFarlane's unexpected decision last week to attend the talks was intended primarily to "send a signal" to the Soviets that Shultz, who will be principal spokesman, speaks with President Reagan's full backing.

"McFarlane will be closer to co-chairing the delegation than being just another member," said a White House official. He said McFarlane, who has been chairman of an intergovernmental group that sought to resolve differences within the adminstration over arms control policy, had "agonized" for several weeks over whether to attend the meetings with Gromyko.

Officials disclosed yesterday that sitting in on the meetings with Gromyko will be Shultz, McFarlane, special advisor Paul H. Nitze and U.S. Ambassador to Moscow Arthur A. Hartman. A Russian-speaking National Security Council official, Soviet specialist Jack F. Matlock Jr., may sit in as a notetaker.

The U.S. delegation for the talks is unusually large and includes officials who have been at odds on administration arms policy. Among those making the trip are the "two Richards," Assistant Secretary of State Richard R. Burt and Assistant Secretary of Defense Richard N. Perle, whose bureaucratic infighting has been celebrated in a book by Time Magazine correspondent Strobe Talbott and many newspaper and magazine reports.

In addition to Nitze, whose experience at global strategy and U.S.-Soviet diplomacy goes back almost 40 years and who served as chief U.S. negotiator in the 1981-83 intermediate-range nuclear force (INF) negotiations with the Soviet Union, the Shultz party includes retired general Edward L. Rowny, who was chief U.S. negotiator in the 1982-83 Strategic Arms Reduction Talks (START).

Earlier, Nitze and Rowny were thought by many to be vying for the main role in any new round of negotiations that could result from next week's meeting with Gromyko. Nitze said last week, however, that he will not accept the post of negotiator in any new round, preferring for personal reasons to limit his role to that of senior adviser.

Others in the U.S. party are Kenneth L. Adelman, director of the Arms Control and Disarmament Agency; Lt. Gen. John T. Chain Jr., director of the State Department bureau of political-military affairs and Vice Adm. Arthur S. Moreau, special assistant to the chairman of the Joint Chiefs of Staff, as well as Hartman, Matlock and NSC arms control specialist Ronald F. Lehman II.

On the eve of the departure, Reagan received special appeals from separate groups of U.S. senators.

Republican Sens. Steven D. Symms of Idaho and Jesse Helms and John P. East of North Carolina asked that Soviet violations of previous arms control agreements have a central place in the talks.

Administration sources said Shultz is prepared to discuss violations charges with Gromyko, especially the U.S. charge that a radar being built in central Siberia is a violation of the 1972 ABM treaty.

Sen. Spark M. Matsunaga (D-Hawaii), joined by several other senators, suggested that Shultz discuss with Gromyko a joint U.S.-Soviet ceremony on April 25 to commemorate the linkup of U.S. and Soviet forces as triumphing allies in Nazi Germany in 1945.