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