While the Marvel Cinematic Universe was inspired by the characters from Marvel Comics, there have always been ways that the movie versions of Marvel, and specifically the "Guardians" characters have differed from their comic counterparts. Sometimes those changes are significant, but other times they’re just cosmetic. Dave Bautista’s Drax in "The Guardians of the Galaxy" was one of those characters who has a very different look in the movies because he’s gray, not green.