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