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