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