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