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