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)(15,19)(16,27)(17,20)(18,23)(21,26)(22,25)(24,28)(5,6)(7,10)(8,9)(11,12)(13,15)(14,19)(16,25)(17,26)(18,24)(20,21)(22,27)(23,28) involution — undirected(5,7,8,11)(6,10,9,12)(14,20)(15,24)(17,25)(19,27)(21,28)(22,23)(6,9)(10,12)(13,16,18,26)(14,21,23,27)(15,25,24,17)(19,20,28,22)(1,3,4,2)(15,24)(16,26)(19,28)(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.