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