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