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