Line the bottom of an 8-inch round cake pan with parchment paper. In medium bowl, whisk flour, baking powder and salt. Using an electric mixer, beat sugar and butter on low until smooth. Add egg whites and vanilla; beat on medium until thick, about 1 minute.
Add coconut milk beverage and half the dry ingredients; beat on low 30 seconds. Add remaining dry ingredients and beat on low 30 seconds, then on medium until blended, about 30 seconds more. Fold in three-quarters of the diced peaches; refrigerate the rest.
Transfer batter to pan. Bake at 325º until a toothpick inserted into the center comes out clean, about 1 hour. Cool cake in pan on rack. Run knife around pan edges to release cake.
Invert cake onto plate; peel off parchment. Spread top of cake with whipped cream; garnish with the remaining diced peaches.