Here's how you can sign it:
1. Pouring motion: Make a "C" shape with your dominant hand (thumb and pinky extended, other fingers closed). Move your hand down in a pouring motion as if you're pouring coffee from a pot.
2. "Drink" sign: After the pouring motion, bring your hand to your mouth, making a "drinking" motion.
You can also use the sign for "cup" and then the sign for "coffee" to express the same thing.
Remember that sign language can vary slightly depending on regional dialects and individual signers.