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