query_posts: display all categories

Create a code to show all post of each of my categories:

<li>
    <a>La Boca</a>
    <ul class="sub-menu">
        <?php
        query_posts( array ( 'category_name' => 'La Boca', 'orderby' =>         'menu_order', 'order' => 'ASC', 'showposts' => -1 ) );
        while ( have_posts() ) : the_post(); ?>
        <li>
            <a href="<?php the_permalink() ?>"><?php the_title(); ?></a>
        </li>
        <?php endwhile;wp_reset_query();?>
    </ul>
</li>

The problem with this code is that I have to be repeated for each of the categories, there is a way for all categories will be automatically loaded? for example with a variable where it says “category_name”?

Thanks for the help