I don’t have much capsize experience, but seeing as nobody else has answered…
The boat doesn’t sail away because you should be hanging onto it, it is full of water and very heavy, and it is going to tend to head up to wind and stop as soon as it gets any way on. A runaway Wayfarer that was already swamped would probably capsize again very quickly.
I have read that you should hang onto the bow to act as a sea anchor, so that the wind turns the boat head to wind. However this would make it rather difficult to get back aboard, the easiest way to do that being at the stern. The boat will be low in the water but also rather unstable so boarding over the stern is less likely to roll it over.
If you have sea room, go on a broad reach with the bailers open, and the boat should empty itself pretty quickly.