Coloring from a certain image in Volume 12, which just came out. It's different from their other encounters because while Shizuo is angry, he's also calm.
And apparently this is expressed by the sunglasses being put away and his hair being crazier than ever.
It's a dark scene! Even with using bright colors, even the hair seems a little dark. Which is fitting, given the setting details. Izaya's coat has a bit of coloring to it for a little contrast between the two sides.