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