Is it appropriate to copy a drawing from a book in my master thesis?
Well, to my eye this is a good case of improving the state of the art, of course citing appropiately your sources. It is the same as quoting from a book.

On the other hand, if the publisher is especially nitpicking, maybe you could just use a software editor to re-create the drawing (still sourcing!) instead of using the "edited" drawing from a book.