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