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)(11,20,23,29)(12,17)(13,18)(14,28)(15,19)(16,21,31,24)(22,34,37,39)(25,32)(26,33)(27,38)(30,35,40,36)(1,3,4,7)(2,5,6,8)(9,11,13,24,15,23,14,21)(10,16,18,29,19,31,28,20)(12,22,26,36,25,37,27,35)(17,30,33,39,32,40,38,34)(11,21,23,24)(12,25)(16,29,31,20)(17,32)(22,36,37,35)(26,27)(30,34,40,39)(33,38)(2,6)(5,8)(9,12,13,26,15,25,14,27)(10,17,18,33,19,32,28,38)(11,22,24,36,23,37,21,35)(16,30,29,39,31,40,20,34)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.