Signed paperwork, left downpayment on new car, haven't received car 1 week later. Can I cancel?

6 days ago, I agreed to buy a new car off the lot. Signed paperwork and left down payment. They had to prep car and add some accessories. Promised delivery in 2 days, six days later, car is still with the dealer and has yet to be driven off the lot. Can I cancel this purchase without penalty. It should not fall under buyers remorse.