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