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