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