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