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