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