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