As of now, the Allow the "Create page in Confluence" in Jira Automation can only create a page with a customizable title. 
If a page is to be linked back to a Jira ticket, there is no way to do this through automation. 

The ability add a body of text to the page during the automation would work.

Or an option to "link to issue" would work; somewhere to use the issue.url smart value.

Work Around

Manually link the confluence page to the issue after automation has created the page.