WP_Query order posts by category

In a custom WP_Query I want to order posts by category. I mean that I want to show posts with term_id=1291 first and then show other posts. when I use two WP_Query , I cant use pagination.

edited

I tried this at first. I thought when I use post__in, wp_query ,keep posts order in post__in.

$c_cat=$_GET[c_cat]
$query1 = new WP_Query(array(
    'tax_query' = array(
        array(
            'taxonomy' = 'category',
            'field'    = 'term_id',
            'terms'    = $c_cat,
        )
    )
));

$query1_ids=array();
foreach ($query1-posts as $p){
    array_push($query1_ids,$p-ID);
}

//new query, using post__in parameter
$finalQuery = new WP_Query(array('post__in' = $query1_ids));