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