He was part of the Op Art movement. Rayo worked with abstract geometry primarily employing black, white and red. Along their career he has carried out cartoons, engravings and it has cultivated the pure geometric abstraction. He believed that lines and angles that form big abysses.
Among the numerous prizes he obtained as a reward for his art work, he received The Schell in 1958.
He won the Salón de Artistas Colombianos in 1970.
In 1974 he published the book Blind Knot, and recent works in 1994.
One of his most celebrated exhibitions was carried out in the National Room of the Museum of the Palace of fine arts of Mexico, titled "20 years, 100 works: Omar Rayo."
In 1981 he founded the Museum Omar Rayo,in Roldanillo. Today this museum owns 2,000 of Rayo's artwork and some 500 other Latin American artists' works. Contains a library, many modules for expositions, graphic arts workshop and a theater.
In the early hours of June 7, 2010, Rayo collapsed while having breakfast at his Roldanillo residence. He died on the way to a hospital in Cali, Colombia, after having suffered a heart attack.