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