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