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