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