Benchmark Generator Tool

"I am assuming you have the data and plotting is the requirement,
Check references at Data visualization tools for Linux
Most of these should be available on Ubuntu

You can also try the Microsoft Excel Charts technique with
OpenOffice Spreadsheet Charts"

"EDIT sorry I didn't finish reading the question before I posted. However the Phoronix suite does do a nice job of visualising its results for the user if i remember correctly.

Phoronix Test Suite

The Phoronix Test Suite is the most comprehensive testing and benchmarking platform available for the Linux operating system. This software is designed to effectively carry out both qualitative and quantitative benchmarks in a clean, reproducible, and easy-to-use manner. This software is based upon the extensive Linux benchmarking work and internal tools developed by Phoronix.com since 2004 along with input from leading tier-one computer hardware vendors. This software is open-source and licensed under the GNU GPLv3. The Phoronix Test Suite consists of a lightweight processing core (pts-core) with each benchmark consisting of an XML-based profile with related resource scripts. The process from the benchmark installation, to the actual benchmarking, to the parsing of important hardware and software components is heavily automated and completely repeatable, asking users only for confirmation of actions.

100+ Test Profiles
40+ Test Suites
Extensible (XML-based) Testing Architecture
Optional Linux-based LiveDVD/USB Testing Distribution (PTS Desktop Live)
Automated Test Installation
Dependency Management Support
Module-based Plug-In Architecture
Integrated Results Viewer
PNG, JPG, Adobe SWF, SVG Graph Rendering Support
Autonomous Batch Mode Support
Global Database For Result Uploads, Benchmark Comparisons
HTML Documentation Covering Test Profiles, Module Framework
Installed Software, Hardware Detection
System Monitoring Support
Runs On Linux, OpenSolaris, Mac OS X, & BSD Operating Systems"