HOW DO YOU GET RID OF THE FABRIC SOFTNER COLOR OUT OF THE DISPENSER?

There is a chance that it might be permanently staining your dispenser, just soaked into the plastic. It is not a really visible unless it is opened up. You might try bleach or baking soda/peroxide paste.

Fill it with vinegar and run a cycle.

I pour hot water in the dispenser and use a rag or paper towel to clean it out or even old toothbrush- just rinse it out every few months

What have your tried? Oxiclean may do the trick, or Bar Keepers Friend powder. Those work the best for me with tough stains.

I would run a load with vinegar in the dispenser.

Disassemble and then clean thoroughly. Once all build up is removed, clean with hydrogen peroxide to remove color from plastic. Rinse well before assembling again.

It will not hurt anything so why not just rinse the dispenser out?

A Magic Eraser should take off that stain, unless it's gone right into the plastic. I'd run a full cycle through with vinegar added to the dispenser too.

Put water in there to rinse it out

I would rinse it out with cool water and vinegar. You could also peek here: https://silverbobbin.com/how-to-get-fabric-softener-stains-out-of-clothes/#:~:text=Fabric%20softener%20can%20leave%20a,dish%20soap%2C%20or%20laundry%20detergent.

It's probably permanently stained the plastic, unfortunately. You could try rubbing some bleach around in there with a rag. Try seeking out fabric softener without any dyes to prevent this in the future, if any exist.

What I personally do is just I fill it with vinegar and run a cycle.