Remove towel from cake. Use parchment paper to lift cake from pan; spread cake with Cool Whip
mixture. Starting at one long side, roll up cake, peeling off parchment as cake is rolled. Diagonally cut off one end of cake; reserve. Place cake on platter; place removed piece, diagonally-cut side facing out, next to log. Frost with remaining Cool Whip
, leaving exposed ends unfrosted. Sift cocoa powder over cake.