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