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