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