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