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