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)(11,14)(12,16)(13,17)(15,19)(18,22)(20,21)(23,24)(25,26)(27,34)(28,38)(29,32)(30,33)(31,37)(35,36)(39,40)(3,7)(5,8)(9,11)(10,14)(12,18)(13,19)(15,17)(16,22)(20,23)(21,24)(25,27)(26,31)(28,35)(29,36)(30,37)(32,39)(33,34)(38,40) involution — undirected(1,2)(3,5)(4,6)(7,8)(9,11,13,19)(10,14,17,15)(12,18,21,24)(16,22,20,23)(25,28,30,32)(26,29,33,38)(27,35,37,39)(31,36,34,40)(9,11)(10,15)(12,18)(13,19)(14,17)(16,23)(20,22)(21,24)(25,29,30,38)(26,32,33,28)(27,36,37,40)(31,39,34,35)(1,3)(2,5)(4,7)(6,8)(9,10)(11,14)(12,20)(13,17)(15,19)(16,21)(18,23)(22,24)(25,26)(27,34)(28,29)(30,33)(31,37)(32,38)(35,40)(36,39) involution — undirected(1,2)(3,5)(4,6)(7,8)(9,12)(10,16)(11,18)(13,21)(14,22)(15,23)(17,20)(19,24)(25,27)(26,31)(28,35)(29,36)(30,37)(32,39)(33,34)(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.