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