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