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