Store it as VARCHAR(36) if you’re looking to have an exact fit, or VARCHAR(255) which is going to work out with the same storage cost anyway. There’s no reason to fuss over bytes here.
Remember VARCHAR fields are variable length, so the storage cost is proportional to how much data is actually in them, not how much data could be in them.
Storing it as BINARY is extremely annoying, the values are unprintable and can show up as garbage when running queries. There’s rarely a reason to use the literal binary representation. Human-readable values can be copy-pasted, and worked with easily.
Some other platforms, like Postgres, have a proper UUID column which stores it internally in a more compact format, but displays it as human-readable, so you get the best of both approaches.