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