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