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