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