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