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