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