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)(25,26,30,33)(27,34,31,28)(29,37,38,32)(35,36,39,40)(1,3,5,8)(2,6,4,7)(9,11,14,13)(10,12,15,16)(18,23)(19,20)(27,31)(28,34)(35,39)(36,40)(2,4)(6,7)(10,15)(11,13)(17,19,22,20)(18,24,23,21)(25,27,30,31)(26,28,33,34)(29,35,38,39)(32,36,37,40)(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)(26,31)(27,33)(29,36)(30,34)(32,39)(35,37)(38,40)(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)(26,32)(27,35)(28,36)(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.