WordPress: Custom Loop with WP_Query and Transient

header.php

function shireman_books_header_loop( $args ) {
	global $post;
	$defaults = array(
		'orderby'                => 'rand',
		'post_type'              => 'we_published-book',
		'posts_per_page'	 => 9,
		'post_status'		 => 'publish',
		'no_found_rows'          => true, // counts posts, remove if pagination required
		'update_post_term_cache' => false, // grabs terms, remove if terms required (category, tag...)
		'update_post_meta_cache' => false, // grabs post meta, remove if post meta required
	);
	$args = wp_parse_args( $args, $defaults );

	if ( false === ( $bookthumbs = get_transient( 'we_books_header_' . $post->ID ) ) ) {
		$bookthumbs = new WP_Query( $args );

		// Set transient for 1 day
		set_transient( 'we_books_header_' . $post->ID, $bookthumbs, 60*60*24 );
	}

	if ( $bookthumbs->have_posts() ) {
		echo '<ul>';
		while ( $bookthumbs->have_posts() ) : $bookthumbs->the_post();
			if( has_post_thumbnail() ) {
				printf( '<li><a href="%s" title="%s"><span class="roll" ></span>%s</a></li>', get_permalink(), get_the_title(), genesis_get_image( array( 'format' => 'html', 'size' => 'book-small', ) ) );
			}
		endwhile;
		echo '</ul>';
	}

	wp_reset_query();
}