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