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)(13,14,18,17)(15,20,16,19)(21,22,25,26)(23,27,28,24)(5,6,8,9)(7,11,12,10)(13,15,18,16)(14,19,17,20)(23,28)(24,27)(6,9)(10,11)(15,16)(19,20)(21,23)(22,24)(25,28)(26,27) involution — undirected(1,2,3,4)(5,6)(7,10)(8,9)(11,12)(13,16,18,15)(14,19,17,20)(21,24)(22,23)(25,27)(26,28)(5,7,8,12)(6,10,9,11)(13,17,18,14)(15,19,16,20)(21,22)(23,24)(25,26)(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.