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