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