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