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