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