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