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