From what I can see, the louvers on the diffuser are aimed away from the return grille. In which case, the supply air should be blown away from the return. In fact, blowing air away from the return could enhance the air flow toward the return.
In general, though, all diffusers have throws that are vary with supply air flow. The throw is the distance the air will flow before reaching a terminal velocity of 50 fpm. In designing supply air systems, the goal is not to have the return air opening toward the outer edge of the throw. That means that the supply air diffuser is usually placed as far away from the return as possible. That being said, one manufacturer used to make a supply air diffuser that had the return in the middle of the diffuser. The theory was that the movement of the supply air helped pull air toward the return air opening. I believe it didn't succeed because of the logistics of installing the diffusers.
I will also add that no matter how return air diffusers are designed, they usually do not work as designed. The only ones that have a chance of working right are ducted ones. Even then, most of these systems are not balanced, and return air systems need to be balanced just as supply air systems do.