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)(13,14,17,22,18,21,15,19)(16,24,23,20,26,27,25,28)(5,7)(6,9)(8,12)(10,11)(13,15,18,17)(14,19,21,22)(16,23,26,25)(20,27,28,24)(1,2,3,4)(13,16)(14,20)(15,23)(17,25)(18,26)(19,27)(21,28)(22,24)(7,12)(9,11)(14,21)(19,22)(20,28)(24,27) involution — undirected(6,10)(9,11)(13,15,18,17)(14,19,21,22)(16,23,26,25)(20,27,28,24)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.