presto-main/src/main/java/io/prestosql/util/GraphvizPrinter.java/NodePrinter/visitLimit
class NodePrinter:        @Override
        public Void visitLimit(LimitNode node, Void context)
        {
            printNode(node, format("Limit[%s]", node.getCount()), NODE_COLORS.get(NodeType.LIMIT));
            return node.getSource().accept(this, context);
        }