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