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