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