Rather than considering a GUI, you could develop a Perl web app that runs locally on your PC. Start by installing
Apache.
CGI::Application describes itself as "a mature, lightweight, flexible MVC framework for web application development". In pratice This tutorial gets you started in about 30-40 lines of code.
The graphs could be done server side (eg using CGI::Application::GDGraph::lines_ap). Alternatively you could do it client side. Just google for one of the many freely available javascript scripts.
Update: fixed GD Graph reference.