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