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