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