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