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