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)(26,27)(28,35)(32,34)(36,37)(6,8)(11,18)(12,15)(19,24)(20,23)(25,26,30,27)(28,33,35,31)(29,34,38,32)(36,39,37,40)(5,6,7,8)(9,11)(10,15)(12,17)(13,19)(14,18)(16,23)(20,21)(22,24)(25,27,30,26)(28,31,35,33)(29,34,38,32)(36,39,37,40)(1,2)(3,4)(9,12,14,15)(10,11,17,18)(13,20,22,23)(16,19,21,24)(25,28,30,35)(26,31,27,33)(29,37,38,36)(32,40,34,39)(9,13,14,22)(10,16,17,21)(11,19,18,24)(12,20,15,23)(25,29)(26,32)(27,34)(28,36)(30,38)(31,39)(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.