If you look in the plugin files, you will find a folder called templates. There is an exemplar template in there for infinite scroll.

Ah. Something like this then (a modification of that file):

<?php
/**
 * Search & Filter Pro 
 *
 * Sample Results Template
 * 
 * @package   Search_Filter
 * @author    Ross Morsali
 * @link      http://www.designsandcode.com/
 * @copyright 2015 Designs & Code
 * 
 * Note: these templates are not full page templates, rather 
 * just an encaspulation of the your results loop which should
 * be inserted in to other pages by using a shortcode - think 
 * of it as a template part
 * 
 * This template is an absolute base example showing you what
 * you can do, for more customisation see the WordPress docs 
 * and using template tags - 
 * 
 * http://codex.wordpress.org/Template_Tags
 *
 */

if ( $query->have_posts() ) {
 ?>
 
 Found <?php echo $query->found_posts; ?> Results<br />
 <div class='search-filter-results-list'>
 <?php
  while ($query->have_posts())
  {
   $query->the_post();
   
   ?>
   <div class='search-filter-result-item'>
    <h2><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></h2>
    
    <p><br /><?php the_excerpt(); ?></p>
    <?php 
     if ( has_post_thumbnail() ) {
      echo '<p>';
      the_post_thumbnail("small");
      echo '</p>';
     }
    ?>
    <p><?php the_category(); ?></p>
    <p><?php the_tags(); ?></p>
    <p><small><?php the_date(); ?></small></p>
    
    <hr />
   </div>
   
   <?php
  }
 ?>
 </div>
<?php
} else {
 
 //figure out which type of "no results" message to show
 $message = "noresults"; 
 if(isset($query->query['paged'])) {  
  if($query->query['paged']>1){
   $message = "endofresults";
  }
 }
 
    if($message=="noresults") {
    ?>
 <div class='search-filter-results-list' data-search-filter-action='infinite-scroll-end'>
  <span>No Results Found</span>
 </div>
 <?php
    } else {
 ?>
 <div class='search-filter-results-list' data-search-filter-action='infinite-scroll-end'>
  <span>End of Results</span>
 </div>
 <?php
 }
}
?>