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