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