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