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