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