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