Not sure if you’re looking for an “automated” way of doing this, but in code you can get an array of all co-authors by using $authors = get_coauthors();
. Once you have your authors array, you can loop through it and use each author object’s ID to get posts by that author:
$authors = get_coauthors();
foreach ( $authors as $author ) {
$args = array( 'author' => $author->ID );
$posts = get_posts( $args );
// echo out your posts
}