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