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