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