Colors can attract sharks visually. A dive buddy of mine was spearing < 30ft. He had on some neon green gloves, grossly bright. Long story short, a lemon shark comes in his vicinity and is immediately attracted to his hands for some odd reason. He fends off the shark several times as it darts towards his free hand thats not holding the grip of the speargun. Finally, he says F this and drops the gloves and the shark follows them as they go down to the bottom and snatches them from sight. The shark was gone and left him alone. Weird stuff... But you are in a wild environment, and no matter your experience you can't predict a wild beast all of the time.
I recommend you blend in with your environment and dive safe. Your buddy should know your diving abilities if you're going to trust him with your life. But, you can't put all of the weight on your buddy neither. You must know your own ability as well.
If you want the bright colors as a visible safety net in fear of drowning, that doesn't sound like safe diving.