Beat cream cheese with a stand mixer fitted with a paddle attachment on medium speed until whipped and creamy, about 1 minute. Slowly add powdered sugar and vanilla, and beat until smooth, about 1 more minute. Fold in whipped topping, strawberry preserves, and 6 cups (approximately 2 pounds) of the sliced strawberries. Sprinkle each serving evenly with graham crackers, and top evenly with remaining sliced strawberries.