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