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