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