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