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