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