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