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