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