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