There is no quick option to export a task template, but it is possible to get your Template into an Excel or PDF sheet with a little perseverance.
1) Create a project and add the task template(s).
2) Now that you have a project that contains all of the relevant information, go to the top of the project page and hover over the Details section. In the top right of that section, you'll see an option for 'Task Report' appear.
3) This will redirect you to the Reports page, displaying the recently created project with all of your template tasks listed. From here you have the option to export to PDF or Excel file by clicking the export options in the Toolbar.