While you can send messages from the "Email Guests" messaging feature, the message templates themselves do not match the chosen website design template (other than the primary color).
Something you might consider is taking a screenshot of your website "Home Page", then upload that image as a photo to an email message you send to your guests. In this way, you will be able to represent your website design.
Find out how to take a screenshot here. You can choose instructions for Windows or Mac.
After you take a screenshot of your "Home Page", you can add it as a photo to an email message in step #2 of the composition process.