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