Contact Form 7 has some special mail tags (http://contactform7.com/special-mail-tags/)
You can insert them into the Message Body field or other fields in the Mail section.
[_remote_ip]– This tag will be replaced by the sender’s client IP address.[_user_agent]– This tag will be replaced by the sender’s user agent information.[_url]– This tag will be replaced by the URL of the contact form.[_date]– This tag will be replaced by the date of the submission.[_time]– This tag will be replaced by the time of the submission.[_post_id]– This tag will be replaced by the ID of the post which contains the contact form.[_post_name]– This tag will be replaced by the name (slug) of the post which contains the contact form.[_post_title]– This tag will be replaced by the title of the post which contains the contact form.[_post_url]– This tag will be replaced by the permalink of the post which contains the contact form.[_post_author]– This tag will be replaced by the author name of the post which contains the contact form.[_post_author_email]– This tag will be replaced by the author email of the post which contains the contact form.
So [_post_url] should do the trick 😉