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