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