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)(11,17)(12,15)(13,16)(14,19)(18,23)(20,22)(21,24)(25,26,31,34)(27,36,37,32)(28,38,39,30)(29,35,40,33)(1,3,4,7)(2,5,6,8)(9,11)(10,14)(12,18)(13,19)(15,21)(16,17)(20,24)(22,23)(25,27)(26,32)(28,33)(29,30)(31,37)(34,36)(35,39)(38,40)(2,6)(5,8)(9,12,13,20)(10,15,16,22)(11,18,19,24)(14,21,17,23)(25,28,29,36,31,39,40,32)(26,30,35,27,34,38,33,37)(10,16)(14,17)(15,22)(21,23)(25,29,31,40)(26,33,34,35)(27,30,37,38)(28,36,39,32)(11,19)(14,17)(18,24)(21,23)(25,30,29,27,31,38,40,37)(26,28,35,36,34,39,33,32)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.