I don't mean to be the bearer of bad news, but please be aware that this isn't a supported client.
Using it isn't an issue, but it isn't a maintained part of the product or provided for customer use, it would be like using a bespoke written XOG client. If it is successful that is fine, but if it fails, the same problem would have to occur with the supported xog client in order for it to be a viable fault.
That said, it can be used and not only on servers. However, the invocation as it is given isn't suitable (namely, the classpath is insufficient and you'll hit lots of 'class not found' errors, and the memory settings aren't supplied for it to use).
To assist with that, I would suggest creating a .bat file in the place you installed the XOG client to and populating it with the following:
@echo off
setlocal enableDelayedExpansion
for %%i in (lib\*.jar) do set MYCP=!MYCP!;%%i
set MYCP=%MYCP:~7%
start /MIN java -cp %MYCP% -Xms512m -Xmx1024m com.niku.xog.gui.XogGui %CD% %CD%
You can adjust/tune the memory parameters as preferred.
This should then be able to run from a client, but it still isn't applicable for use with OnDemand environments (sorry) or some on-premise ones because this doesn't work with https/ssl connections.