Yes, “representative colors” were used. They may have combined visible with non-visible images from infrared, ultraviolet and/or X rays where they had to represent a non-visible spectrum in a color we can see. It could also be an image where they isolated emission signatures from different elements and showed them in different colors. Unfortunately they don’t usually give details like that. I think it would be interesting to many of us.
Good comment / explanation. I have to admit, the image as presented almost looks like some vast alien life form from Star Trek!