By default the repository is saved in C:\Repositories, but in live servers it is not safe to store data in C: drive so it is good to save to other drives. To change the path of the repository follow the steps:-
1. Open Visual SVN Server
2. Go to the root node of the repository and select properties
3. Change the path of the repository root to desired path of your choice.
Click OK and your done,. If you have files and data in your old repository path, you can copy paste your data to the new path so that your old data remain intact.