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