Add the milk, dry pudding mix and lemon peel; beat until smooth. In a blender, process 1/2 cup strawberries and grape juice until blended.
Tear cake into 1-in. cubes; place a third in a trifle bowl or 3-qt. serving bowl. Top with a third of the pudding mixture and half of the remaining strawberries.
Drizzle with half of the strawberry sauce. Repeat. Top with remaining cake and pudding mixture. Cover and refrigerate for at least 2 hours.