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