In terms of Paula's comments, we may all be in the same boat. I do, however, understand some of the things she says. When she speaks of "colors" she is most likely referring to the variety of sounds emanated from a vocalist. The sounds, if heard with one's eyes closed, could evoke images of colors.
Step2
Randy is the one who is the most charming and relatable to many demographics. Some of the things he will say are:
1) "That was the bomb!" which translates to "That was great! You are incredible and explosive!"
2) "That was a little pitchy" which simply means that the vocalist was never securely within the targeted melody notes in the song.
Step3
Simon is the one for offering more animated criticisms. He may say things like, "That was all a bit cabaret" which would just mean that the performance was a little cheesy and more similar to a theater performance than that of a pop star. He will also use variations like, "That was a bit old fashioned," "It was like bad wedding singing" or "It was like bad karaoke." These all mean that the performances were not adequate and representative of a pop star, but more like an amateur.