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