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