It's easy to see what the grip looks like for inswing and outswing. It's also easy to see if you are making chances of swing improve by having an upright seam position as the ball travels towards the batsman.
The difficult, almost imperceptible, difference is your wrist position at the point of delivery. It's one of those 'feel' things you get as a bowler that can be hard for a coach to demonstrate.
In seam up bowling (rather than swing), the idea is to hit the pitch with the seam. The way to do that is to release the ball with a vertical seam and your wrist following right behind, facing the batsman. This makes sense because if your wrist does not follow your fingers the seam will wobble and be less effective.
Swing bowling takes this principle and allows you to encourage late swing through both wrist and angled seam position (as long as you don't scramble the seam in the process).
So the seam stays upright, what do you do with your wrist?
This is where things start to get hard to explain.
In fact, I thought long and hard before writing this article. Is it worth trying to explain when wrist position is so reliant on the bowler getting the right feel? I thought on balance I would at least try. Here is my attempt.
If you want to bowl outswing, you soften the wrist a little so the wrist almost leads the fingers. If you want to bowl inswing you keep the wrist firmer.
Another way of looking at it is from Bob Woolmer:
"The best way of visualizing the correct arm and wrist action for the outswinger is to imagine putting a pole into the pitch on the bowling crease. Now try bowling around the pole, your arm coming round it on the right hand side... go 'round the pole' with your wrist only"
For inswing, Bob advised going round the other side of the pole.
Clearly this very small change takes some practice to get the exact feel of release and seam position you need. This can be difficult of you are practicing in conditions where the ball is not swinging.
That may be the reason swing bowling is such a mystery. Conditions have to be right and even your pace on the day makes a difference to how much it swings.
But with practice, you can get the feel you are after and start swinging the ball more regularly.