The supergraph gives you a visual representation of how your campaigns have been performing over time. You can find it in the 'Overview' tab in your Dashboard.
There are 3 variables that affect the data in the supergraph:
Metrics: You can show the relationship between Clicks, Impressions, Conversions, CPM, CPC, CPA, and Spend.
Daily, Weekly, Monthly: In the right-hand corner you can choose how you want your data to be presented - precise data for each day, accumulated data for weeks, or months.
Date Range: You can choose what timeframe you want to report on. Note: This will rule what data the entire Dashboard reports on.