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