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