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)(27,33)(28,29)(30,34)(31,37)(32,38)(35,39)(36,40) 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)(26,31)(28,35)(29,36)(30,37)(32,39)(33,34)(38,40)(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)(25,28,30,38)(26,32,34,29)(27,35,37,40)(31,39,33,36)(1,4,5,3)(2,6,7,8)(9,11)(10,14)(12,17)(13,18)(15,21)(16,22)(19,23)(20,24)(25,29,30,32)(26,28,34,38)(27,36,37,39)(31,35,33,40)(1,2)(3,6)(4,8)(5,7)(9,12)(10,16)(11,17)(13,20)(14,22)(15,19)(18,24)(21,23)(25,27)(26,33)(28,35)(29,39)(30,37)(31,34)(32,36)(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.