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