Is there a way to open (visual) revision graph of a project only using command line?
Sure!
The command would look like TortoiseProc.exe /command:revisiongraph /path:<path-to-checkout>
TortoiseProc.exe /command:revisiongraph /path:<path-to-checkout>
You should consult automating TortoiseSVN for an understanding of the TortoiseSVN CLI.