On automorphisms of a strongly regular graph $(784,116,0,20)$

It is studied the group $G$ of automorphisms of a strongly regular graph with parameters $(784,116,0,20)$. We proved that if $G$ contain an element of prime order $p$, then $p\in\{2,7\}$. As a corollary, it is followed that the group of automorphisms of this srg is not quasy primitive.