There's only one way to get a cursor that looks like the one in the post: Go to Settings > Ease of Access > Mouse pointer, choose the multicolor pointer box, click the plus sign of the "Pick a custom pointer color" line, and use the color picker to choose white.
Fortunately, reversing this is simple: Just click either of the first two boxes under "Change pointer color". The leftmost one is the Windows default, which will also restore the I-beam text cursor.