Hygieia has quite commonly come down to us in classical sculpture, even thou I must admit that I only can reckon two museums where I've seen such pieces. She is portrayed as a virgin with a kind face expression, in a long robe with a snake which she is feeding from a bowl.
Hygieia from Zappeion, Athens, of the Hope type. From the second century AD, copy of a Greek original from the third century BC.
Hygieia from Epidaurus, no dating was offered but you can clearly see the snake, which is why I uploaded this shot.