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