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