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