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