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