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