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