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