Ed's face was red as a beet when he realized everyone was listening to his singing.
An person can also turn pink with mild embarrassment or be red with anger.
White as a sheet
When a person is ill, his or her face can be as white as a bed sheet.
Everyone knew that Jill should leave the office early because she was as white as a sheet.
A person can also be white with fear.
Sing the blues
To complain about one's troubles. A person who is blue is sad.
Thomas has been singing the blues ever since he was named manager of the department.
A type of jazz music that is rather melancholy is called the blues.
Black mood
A very bad mood, anger or mild depression
Bill is a great guy, but avoid him when he is in a black mood.
Green
To be envious, or jealous of another person
Joan was green when she heard that Ed had been promoted to supervisor after just six months with the company.
Green has many connotations. It can be a reference to money as it is the color of the U.S. dollar. Also, green is used to describe people and policies that protect the environment.