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