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