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