Here is a few pics I took a couple of years back in the Cayman Islands, you can see some of the camo changes including the defensive white color.
Both squids and octopus pulse colors. I had a small squid hang out with me on a night dive in Cozumel that would just pulse and sit 1 foot in front of my eyes. We played for about 45 minutes to and an hour before he moved on.
That is really cool! I think thatd scare the crap out of me, if i accidentally swam upon one of them while they were camo. and suddenly came visible! haha