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