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