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