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