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