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