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