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