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