Data imports an additional task attribute which is set to 'allow Colour-By' on the plan. Change the actual colour it uses, so that they are more pronounced.
Please complete the following steps:-
Creating the Lookup Table
Select Planning, Additional Task Data.
Click Edit, New Row.
Enter a Code and Display Name.
Use the Type drop-down and select Lookup Table.
Select the check boxes for Allow Colour-By, Show in Task Overview, Show in Planning Screens.
Click Apply, OK.
Creating the Custom List
Select Tools, Custom Lists.
Use the drop-down and select the Lookup Table just created.
Click Edit, New Row.
Enter the Sequence, Value and Fill Colour for the attributes.
Click Apply, OK.
Applying the Attributes
On the Gantt, select a Task.
Double-click the Task or click onto Edit Tasks.
Click the Attributes tab.
Use the Custom List drop-down and select an option and it will apply.
Colouring the Gantt
On the top toolbar, next to field Colour By, use the drop-down and select the Custom List created.
Any Tasks with the attributes applied will colour on the chart. This also works on Agenda and Work List views.