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