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