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