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