You could do that with code like:
Code:
Sub Demo()
Dim Rvn As Revision
With ActiveDocument
For Each Rvn In .Revisions
With Rvn
Select Case .Type
Case wdRevisionInsert, wdRevisionMovedTo
.Range.HighlightColorIndex = wdYellow
End Select
End With
Next
.Revisions.AcceptAll
End With
End Sub
Note that deletions etc. are simply deleted - it's a bit hard to highlight something that's been deleted.
IMHO, though, you'd do better to accept or hide all the deletions, leaving just the additions/moved content as visible tracked changes, formatted as red (a track change option), for example, so the change bars would remain for deletions and the new content would have both a change bar and coloured formatting to make them stand out. Then, immediately the update is published, you can accept all the changes before starting on the next revision cycle. That's how it was done when I managed instruction manuals for the organisation I formerly worked with. Worked well. In addition, we archived each edition with the tracked changes in-situ to provide a permanent record of what had changed with each iteration.