There are a few different types of Automa cards--a few have different backs. They came shrinkwrapped within the same deck of cards, so I bet you have them. If you really can't find them, look in the objective card deck--they're the same size, so they may have gotten shuffled in there by accident.
Thanks Jamey, found them! I was was just unboxing everything and didn't realize which cards were needed for the automa module.