I could make an inference her favorite color was yellow and purple because she wore a lot of yellow and purple dresses. I believe she also loved hats. Keep in mind she is known for being stylish and introducing new fashions to the White House. She liked many bright colors like pink and orange.
Fashion and pearls and her family.
pink
Gold
Janet Bouvier Auchincloss Morris
Given her love for aviation, her favorite color most likely was the bright blue sky.
Jacqueline Bouvier
It is housed in in Boston, Massachusetts, in the Kennedy Library.
John Vernou Bouvier (also known as "Black Jack")
daisy
Red
Gray
Jacqueline Lee Bouvier was John F. Kennedy's first lady.