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