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