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