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