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