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