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