You could for example change
<?php next_post_link ( '%link →', '%title', true, '', 'category' ); ?>
to <?php next_post_link ( '<div style="float: right">%link →</div>', '%title', true, '', 'category' ); ?>
You could for example change
<?php next_post_link ( '%link →', '%title', true, '', 'category' ); ?>
to <?php next_post_link ( '<div style="float: right">%link →</div>', '%title', true, '', 'category' ); ?>