One vertex per element, one color per generator, with an edge from x to x·s.
(2,4)(9,10,15,21)(11,22,26,18)(12,27,31,36)(13,20,14,19)(16,25,33,24)(17,29,37,30)(23,38,40,32)(28,34,39,35)(1,2)(3,4)(5,6)(7,8)(9,11,14,25,15,26,13,24)(10,16,20,18,21,33,19,22)(12,28,30,40,31,39,29,23)(17,34,27,38,37,35,36,32)(6,8)(9,12)(10,17)(11,23)(13,30)(14,29)(15,31)(16,32)(18,35)(19,27)(20,36)(21,37)(22,34)(24,28)(25,39)(26,40)(33,38) involution — undirected(2,4)(9,11,15,26)(10,18,21,22)(12,23,31,40)(13,25,14,24)(16,19,33,20)(17,35,37,34)(27,38,36,32)(28,30,39,29)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.