<p>In Cura Slicer, is it possible to change the direction that the filament is laid down when making the top layer?</p>
<p><a href="https://i.stack.imgur.com/6AIdx.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/6AIdx.png" alt="enter image description here" /></a></p>
<p>For example, in the above picture the filiment is laid down at about 45 degrees to the X\Y axis. Can I make it 90 degrees?</p>

Yes with a few tricks:
You could turn the item by 45°, then all layers are turned to follow the local X and Y-axis of the body itself, but not the global X and Y of the printer - there'll be a 45° conversion between the items local coordinates and the printers global ones.
Or you could choose a different upper layer pattern, for example concentric, for the upper and lowermost layer.
If you want to define a specific zig-zag direction, you need to go advanced mode, click the gear and enable "Top/Bottom Line Direction". This now allows altering the direction by setting an angle different from 45°/135°. The setting however is ignored if you don't use Lines or ZigZag