Refreshing Lemon Pie

1 14oz can sweetened condensed milk
1/2 cup lemon juice
1 tablespoon grated lemon peel
2 drops yellow food coloring -- optional
1 8oz carton frozen whipped topping -- thawed
1 graham cracker crust (9 inches)
mint leaves and lemon peel strips -- optional

In a bowl, combine milk, lemon juice, grated lemon peel and food coloring if
desired; mix until smooth (mixture will begin to thicken). Fold in whipped
topping; spoon into crust. Chill until serving. If desired, garnish with mint
leaves and lemon peel strips. Refrigerate leftovers.