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