Choosing and formatting symbols
In line and scatter charts the symbols representing the points can be changed to a different symbol shape or color through the object properties dialog.
On the Line tab of the Data Series object properties dialog, in the Icon section, choose from the drop-down list Select > Symbols. Here you can choose no symbol, a symbol from an inbuilt selection, a more exciting range from the gallery, or if you have pictures you need to use instead, you can insert them using Select > From file.
Symbol selection