Styling done on the Block.php is the same you would do on any other php page. You can style it using CSS. There is a region that goes through each value posted by the form and puts it into the email form. If you wanted to edit the value that is output before the colon, you would want to find this bit of code:
<?php echo(str_replace("_"," ",$pkey)); ?>
and modify it to show something different.