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