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