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