Hi @Nishanth Chakkere,
Thank you for posting in this community.
SharePoint does not natively provide a feature to display site contents in a diagram format.If your goal is to see the content and structure of your site, here's a feature that's outdated but still works: SharePoint Online Content and Structure.
Here are the steps:
- This feature is only available to site administrators, not even site owners with full permissions.
- Please click site collection features under site collection administration> find SharePoint server publishing infrastructure> click activate.
- Please click Manage site features under Site Actions> find SharePoint server publishing > click activate.
- Please visit this URL:
https://yourTenant.sharepoint.com/sites/yourSite/_layouts/15/sitemanager.aspx.
- You can see the structure of your entire site's content. Double-click an item in the left navigation bar to see all of its contents on the right.
As for third-party tools, I'm sorry I can't access information about other third-party software in the forums. Maybe you can look for it yourself according to your needs.
Microsoft maintains a forum: Partner Center where more users programmatically implement some features that are not implemented in Microsoft's official software, and perhaps you can post here to see if anyone has the same needs as you and has solved them.
If the answer is helpful, please click the "Accept Answer", this can make it easier for other community members to see the useful information when reading this thread. Your contribution are highly appreciated.