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