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