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