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