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