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)(11,17)(12,16)(13,15)(14,19)(18,24)(20,22)(21,23)(28,36)(33,40)(35,38)(37,39) involution — undirected(9,11,13,19)(10,14,15,17)(12,20,21,18)(16,24,23,22)(25,26)(27,32)(28,37)(29,31)(30,34)(33,35)(36,39)(38,40)(2,5)(6,8)(26,31)(27,29)(32,34)(33,37)(35,38)(39,40) involution — undirected(1,3,4,7)(2,6,5,8)(10,15)(14,17)(16,23)(22,24)(25,27,30,29)(26,32,34,31)(28,35,36,38)(33,39,40,37)(9,12,13,21)(10,16,15,23)(11,18,19,20)(14,22,17,24)(25,28,30,36)(26,33,34,40)(27,35,29,38)(31,37,32,39)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.