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