Preheat oven to 350 degrees Fahrenheit and grease a 9x13 inch baking pan.
Combine cake mix, 1 cup water, oil, and eggs in a large bowl and mix until smooth.
Pour batter into prepared pan and bake for 30 minutes or until a toothpick comes out clean.
Allow cake to cool for 20 minutes.
Use a fork or the handle of a wooden spoon to poke holes across the entire surface of the cake at 1-inch intervals.
In a medium bowl, dissolve strawberry gelatin in 1 cup boiling water, then stir in 1/2 cup cold water.
Slowly pour the gelatin mixture over the cake, ensuring it fills the holes.
Refrigerate the cake for at least 4 hours to allow the gelatin to set.
Spread whipped topping evenly over the surface of the cake.
Garnish with sliced fresh strawberries before serving.