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