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