The colours of the charts in your reports are determined by the colours that you have assigned to your outcomes in that outcome set. You can change these by navigating to Admin > Templates > Outcome Set > and then in your Outcome Set List, select the Outcome Set you want to edit.
On the next page, next to the Outcome List, click Edit Colours. You will see a number of colour options to select for each outcome. Simply click the colour you want for each outcome.
At the bottom of the page, you can see previews of how these colours will look in your reports. Once you're happy, click Save, and this will change the colours of your charts in your reports.
