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