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