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