By car, take the Mustafapasa road south from Ürgüp. There is also extremely sparse dolmus service from Ürgüp to Mustafapasa, but I don't recommend this because you'll lose too much time waiting around. If you're staying at an inn in town, chances are your hotel owner will provide a transfer or shuttle for a fee, or even for free. Don't be shy to ask.
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.