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