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