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