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