You can try Octopus.do XML generator. Insert the url by using this link and then press Import "Pages only" or "With meta tags" optionally. Octopus.do helps to visualize any website structure from Internet. And the main purpose of Octopus.do to help you create your own site sitemap by using "Content brick method" which is very easy in work, just drag and drop content blocks. Octopus.do also has a low fidelity wireframe collection for prototyping website structure and UX architecture.