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