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