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