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