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