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