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