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