Yellow colour represents happiness, sunshine and joy but it can represent corruption and deprivation. Gold that is a shade of yellow and represents riches and extravagance but also represents tricking, cheating and deceiving. The yellow colour of Gatsby's car represents death since his car ran over Myrtle and he is killed because Wilson thought he was driving the yellow car, which killed his wife. The yellow colour of Pammy's (Daisy's daughter’s) hair represent riches and extravagance but it might also represent the fact that Daisy's daughter is deprived of a good mother since Daisy treats as like an accessory. The twins who wore yellow could represent dishonesty since they support Jordan who has "autumn-leaf yellow" hair. Jordan cheats and is very untruthful. They could represent corruption since they were at Gatsby's party and Gatsby made his fortune through corrupt and illegal ways.
The colour yellow, in THE GREAT GATSBY symbolizes Corruptness. The world of most of the novels´ characters is plagued with corruption.