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