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