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