We have a SEO Sitemap available that is a Format which can be applied to an index block configured to index pages in your site. This will output an XML sitemap.
The Format is generic so it will require modification in order to apply it to your specific URL. Additional information is available in the readme file on the GitHub page.
This Format assumes you have a folder Index Block which indexes from the base folder of a Site and includes only pages and metadata (system and user).
Once you have such an Index Block set up you can implement the site map by:
Create a Template which has just a single
<system-region name="DEFAULT"/>(if you don't already have one).
Create a Configuration called Sitemap with a single XML output and the above Template. Assign the Index Block and Format to that
Create a Content Type called Sitemap and select the Sitemap Configuration. The Data Definition and Metadata Set won't really matter in this case.
Create a Page and assign the above Content Type to it.
Once you have that page created and publish it, you will have a sitemap containing all indexable pages.
Note: Index Blocks will not pick up pages whose hierarchy prevents them from being indexable.