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