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