Well I did not think this was possible until I went and checked. In some previous version of Excel I could not do this. I am currently using Excel 2013.

This is what you want to do in a scatter plot:

1. right click on your data point
2. select “Format Data Labels” (note you may have to add data labels first)
3. put a check mark in “Values from Cells”
4. click on “select range” and select your range of labels you want on the points

UPDATE: Colouring Individual Labels

In order to colour the labels individually use the following steps:

1. select a label. When you first select, all labels for the series should get a box around them like the graph above.
2. Select the individual label you are interested in editing. Only the label you have selected should have a box around it like the graph below.
3. On the right hand side, as shown below, Select “TEXT OPTIONS”.
4. Expand the “TEXT FILL” category if required.
5. Second from the bottom of the category list is “COLOR”, select the colour you want from the pallet.

If you have the entire series selected instead of the individual label, text formatting changes should apply to all labels instead of just one.