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