This recipe is a broad interpretation of Jacob A. Didier's 1909 original and the Casino recipes that follow in Hugo R. Ensslin's 1916 book and other subsequent...
I've managed to find an earlier instance of the casino cocktail; on page 5 of "The Reminder" by Jacob A. Didier (3rd Edition) from 1909. It seems Ensslin copied Didier (the wording is almost the exact same).