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