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