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