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