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