Combine cake mix. 1 cup coconut, water and egg whites; beat 2 minutes at highest speed electric mixer. Reduce speed to low; beat for 1 minute. Pour batter into a greased and floured 13x9x2 inch baking pan. Bake at 350 degrees for 25 to 30 minutes or until a wooden pick inserted in center comes out clean. Cool cake in paj for 10 minutes.
Punch holes in top of cake with a toothpick. Pitt cream if coconut over cake while still warm. Spread whipped topping over cake; sprinkle with remaining coconut. Cover and chill at least 4 hours. Cut cake into squares to serve.