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