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