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