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