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