Load categories colors in advance to avoid

load_categories_colors.php

/**
 * load_categories_colors
 *
 * Load categories colors in advance to avoid
 * multiple queries
 * @author Marcin Zaremba
 */
function load_categories_colors() {
	$cats = get_categories();
	$ids = array();
	
	foreach($cats as $cat) {
		$ids[] = $cat->term_id;
	}

	update_termsmeta_cache($ids);
}

add_action('plugins_loaded', 'load_categories_colors');