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