This is probably not the best advice but it is what I have been doing. I hear better with my right ear so I roll  up the earbud for my left ear and wrap with tape or a rubber band and only use the right ear. That way when I pull it out of my purse it is much less tangled.

You can put perler beads on the earbuds. 🙂 Not that hard and you can choose any colour(s) you like, and the earsbuds wont tangle.

I know two ways that I think are good enough to share. The first one is this way to roll them up. It doesn't take too long doing and it is fast to unfold.

The second way is to not roll them up, but coil them with a blow dryer. Just wrap them around something with the diameter you want the cord to be. Then heat with a blow dryer and let it cool off.

Snapguide has a wrapping technique that I thought was quite elegant too.

How to Coil Your Earbuds

 I do what Niklas suggested in the first video! really easy to get into the habit of doing.

Thank you for your suggestions everyone! The video tutorial Niklas found (#3) was actually really good, so no longer do have this cabled mess in my backpack now