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