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