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