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