Make a new document sized 300x300 and fill it with any color. Now grab your gradient tool and using the settings below:
Start drawing until you get something like this(the result will always differ) :
Now go to Filter>Stylize>Find edges
Press Ctrl+I to invert the image :
Go again to Filter>Stylize>Find edges
And again press Ctrl+I to invert the image:
To remove those ugly colors press Ctrl+Shift+U to desaturate the image:
Duplicate the layer and set blending to screen and lower opacity to 40%. You should have something like this :
Press Ctrl+U to give color.
I used a simple blue color:
You are pretty done. For a better effect I duplicated the layer and added a crosshatch(Filter>Brush Strokes>Crosshatch). Now set blending to overlay.
This is my final result:
