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