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