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