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