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