How to add a sensitivity label to SharePoint document library using GraphAPI

In the SharePoint UI, I can configure a default sensitivity label for a document library by going to Library Settings → Default sensitivity labels and selecting a label (e.g., General \ Anyone (unrestricted)). This applies the label automatically to all newly created or edited Office files within that library.

I'd like to automate this via the Microsoft Graph API instead of doing it manually through the UI.

I am unable to find Graph API request URL to run the API