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