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)(13,14,18,21)(15,22,23,28)(16,20,17,26)(19,24,27,25)(7,8)(10,11)(13,15)(14,19)(16,25)(17,24)(18,23)(20,28)(21,27)(22,26) involution — undirected(2,4)(5,7,9,8)(6,10,12,11)(15,23)(19,27)(22,28)(24,25)(5,8,9,7)(6,11,12,10)(13,16,18,17)(14,20,21,26)(15,24,23,25)(19,22,27,28)(6,12)(10,11)(14,21)(19,27)(20,26)(22,28) 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.