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