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