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