Supply/Demand Curve for Excise tax that's being passed 100% on to consumers
The reason you have trouble with that normal graph is beacause it contradicts your premise. Therefore, you can't use it.

I assume you mean the real burden (incidence) is passed on 100% to the consumers.

In that case you need a graph that allows for that. Your graph implies that both share the tax to some degree. To analyze a tax passed on completely to the consumers you need adequate supply and demand functions that allow for it. 

As you mentioned, one possibility is a perfectly elastic supply function and a standard demand function.

Another possibility is a perfectly inelastic demand function and a normal supply function.

The reason both of these work is because the tax burden is carried by the less elastic side. For one side to carry the full burden we need something to be perfectly (in)elastic.

You have suppliers completely avoiding the tax burden. So you need suppliers to be very elastic compared to demanders. This can be done by making suppliers themselves perfectly elastic. Alternatively you can just making demanders perfectly inelastic and then by contrast the suppliers will be the much more elastic side and not carry any of the tax burden.

After you do that your tax burden area should be only one color.