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