How is the Olympics any different from all other sports events. In general the uniform is designed for optimal performance, and in some sports that means wearing as little as possible – however most events allow individuals to wear more. Some Muslim women occasionally try to compete in specially designed modest track suits.
Among sports that tend to have relatively modest uniforms are baseball, softball, fencing, American and Canadian football (not and Olympic sport), all shooting sports, and all winter sports. On the other extreme there’s swimming.
An exception to all rules is “Beach Volleyball” which is regular volleyball, but with a required “uniform” of a minimal bathsuit for female participants (males where respectable shorts and shirts). The female required uniform suggests that this should not realy be considered a “sport”.