Speed Dial Tiles in Phone App

[Hotdog Molly]

When I open my phone app on my Nexus 5 the first thing that shows up is Speed Dial my contacts are on coloured tiles how do I change the colour of these tiles to what I want

 

[mrsmumbles]

Using the stock dialer, I don't think you can. I've never seen an option for changing the colors of the tiles. I'm wondering myself how colors are assigned by the app.