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