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