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)(15,23)(16,20)(17,22)(18,21)(19,26)(24,28)(25,27) involution — undirected(2,3)(6,9)(10,12)(13,15)(14,19)(16,24)(17,26)(18,25)(20,27)(21,28)(22,23) involution — undirected(1,2,4,3)(5,7,8,11)(6,10,9,12)(13,16,17,18)(14,20,22,21)(15,24,26,25)(19,27,23,28)(1,3,4,2)(15,25)(16,18)(19,28)(20,21)(23,27)(24,26)(6,9)(10,12)(13,16,17,18)(14,21,22,20)(15,24,26,25)(19,28,23,27)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.