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