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