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)(11,15)(12,19)(13,14)(16,20)(17,21)(18,24)(22,23)(25,26,31,35)(27,36,38,32)(28,30,34,39)(29,33,37,40)(2,3)(6,7)(11,17)(15,21)(18,23)(22,24)(25,27)(26,32)(28,37)(29,34)(30,33)(31,38)(35,36)(39,40) involution — undirected(1,3,5,2)(4,7,8,6)(10,14)(15,21)(16,19)(22,24)(1,4,5,8)(2,6,3,7)(9,10)(11,15)(12,16)(13,14)(17,21)(18,22)(19,20)(23,24)(25,28,31,34)(26,30,35,39)(27,37,38,29)(32,33,36,40)(9,11)(10,15)(12,18)(13,17)(14,21)(16,22)(19,24)(20,23)(25,29,31,37)(26,33,35,40)(27,34,38,28)(30,36,39,32)(9,12)(10,16)(11,18)(13,20)(14,19)(15,22)(17,23)(21,24)(25,30)(26,34)(27,33)(28,35)(29,32)(31,39)(36,37)(38,40) involution — undirectedA 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.