Angola's government, the only one on the African continent the United States does not recognize, hassent a new signal to the Reagan administration that it would like to normalize relations, despite differences over the presence of 20,000 Cuban troops here.

A desire to improve ties and growing Angolan concern over the escalation of South African military attacks on its territory were the main impressions gained by a U. S. congressional delegation that ended a 31-hour visit here last night, according to Rep. Howard Wolpe (D-Mich), leader of the group.

The five members of the House of Representatives, all Democrats, were given a top-level reception and the most extensive tour of this Soviet ally that has been accorded to any of the few official U.S. delegations that have visited this country.

The delegation met for one hour with President Eduardo dos Santos. It is believed to be the first time the Angolan leader has met with U.S. officials since he took office two years ago.

The delegation also was taken to the edge of the war zone, 250 miles north of the border of South Africa-administered Namibia, and shown damage from South African air attacks.

After these contacts, Wolpe said: "The Angolans were saying as loudly as can be heard that they want positive relations with the U.S., just like they have with Europe. They can't understand why the United States stands so alone on the subject."

They also emphasized their good relations with the American oil industry since the United States is the major country helping Angola exploit its growing oil discoveries. Angola recently signed a $85 million loan with the U.S. Export-Import Bank to expand its oil industry.

Wolpe, chairman of the House Foreign Affairs Committee's Africa subcommittee, also said the Angolans "find incomprehensible the U.S. preoccupation with South African security concerns when no nation in the region has attacked South Africa." In contrast, the Angolans noted, Angola is subject to virtually daily incursions by South African troops from across the Namibian border without any public criticism being voiced in the United States.

Earlier this month, Angola said South African forces had pushed more than 60 miles into the country to occupy seven towns. Vice Foreign Minister Vennacio de Moura told the congressmen that the South African forces are still holding three of the towns.

South Africa said its forces crossed the border to attack bases of the South West Africa People's Organization (SWAPO), which is fighting for independence for Namibia, controlled by South Africa in defiance of the United Nations. The Angolans say the South Africans hit civilian targets in Angola.

Wolpe said the welcome accorded the congressmen was one of the warmest in their African tour, which has included Zimbabwe, South Africa, Kenya and Somalia. The team left last night for Nigeria, the last stop of the trip.

Considering that the two countries have no diplomatic relations, the level of reception and the rare access to the countryside was significant. Both sides exchanged warm words of friendship at a dinner in Luanda Monday night and a luncheon yesterday in Lubango where the party was taken to see war damage.

Lt. Col. Pedro Soguetao, the military commander in the Lubango region, said there have been more than 1,000 South African actions in the last eight months, mainly reconnaissance flights, but also 156 South African attacks by land forces, helicopter-borne troops and planes. About 120 people were killed and almost 200 were injured, about half civilians, he said.

During the visit, military officials told Wolpe they had just learned of a South African attack yesterday 100 miles to the south in which seven Angolans were killed. They had no other details.

The congressmen were shown what were described as captured South African weapons, many of American origin. An American military aide to the party said much of the U.S equipment was outdated and obtainable through private arms markets. The U.S maintains an arms embargo against South Africa.

Wolpe said there was no movement over the issue of Cuban troops who Angola says are needed because of frequent South African incursions from Namibia.

Dos Santos and Moura, in separate meetings, said once the external cause for the Cuban presence disappears, then there will be no reason for the presence to exist, according to Wolpe.

They were careful, however, not to make a formal connection between the two issues.

Angolan officials also resented the U.S. linkage of diplomatic recognition to the Cuban presence, Wolpe added. They said it was as illogical as if the Soviet Union made the Americans' dominance in Angola's oil industry a barrier to relations.

On the Namibian negotiations, the officials said they would have no objection to U.S. proposals for human rights guarantees in an independent Namibia as long as they were for everyone regardless of race. The Reagan administration has proposed that guarantees be worked out in advance of a settlement.