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