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