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)(13,14,17,18)(15,19,25,24)(16,21,26,20)(22,23,28,27)(5,7,9,11)(6,10,12,8)(13,15,17,25)(14,19,18,24)(16,23,26,27)(20,22,21,28)(2,4)(5,8,9,10)(6,11,12,7)(13,16)(14,20)(15,22)(17,26)(18,21)(19,27)(23,24)(25,28)(2,4)(6,12)(7,11)(13,16)(14,21)(15,23)(17,26)(18,20)(19,28)(22,24)(25,27) involution — undirected(13,14,17,18)(15,24,25,19)(16,20,26,21)(22,23,28,27)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.