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