In a stand mixer, whip together cream cheese frosting, whipped topping, coffee powder, cinnamon and cayenne until fluffy. Spread 1/3 of this mixture on top of the graham crackers. Sprinkle with 1/4 cup of the toffee bits. Layer graham crackers, whipped cream mixture, and toffee bits 3 times more. Cover and refrigerate overnight or for a minimum of 12 hours.