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