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