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