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