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