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