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