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