One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,4)(5,6,8,7)(9,10)(11,20)(12,17)(13,18)(14,27)(15,19)(16,21)(22,34)(23,29)(24,32)(25,33)(26,37)(28,31)(30,35)(36,39)(38,40)(9,11)(10,16)(12,21)(13,22)(14,28)(15,23)(17,29)(18,30)(19,31)(20,27)(24,35)(25,36)(26,38)(32,39)(33,40)(34,37) involution — undirected(2,4)(9,12,15,14)(10,17,19,27)(11,21,23,28)(13,24,25,26)(16,29,31,20)(18,32,33,37)(22,35,36,38)(30,39,40,34)(5,7,8,6)(9,13,15,25)(10,18,19,33)(11,22,23,36)(12,24,14,26)(16,30,31,40)(17,32,27,37)(20,34,29,39)(21,35,28,38)(10,19)(13,25)(16,31)(17,27)(20,29)(22,36)(24,26)(35,38) involution — undirectedA 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.