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