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