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