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