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