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