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