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