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