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