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