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