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