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