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