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