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