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