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