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