Hughes contrasts the gray color of the horses with the intense colors of the environment in which he finds them in "The Horses." How does this color contrast convey the speaker's impression of the horses?

The color contrast convey's the speaker's impression to the horses because in every color that we see, there is always a meaning behind it. For example, the color red represents love. As the speaker tends to describe the horse with the color, he tries to bring out its meaning.