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