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