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