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