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