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