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