How to make graphplot do the same layout every invocation

I am using graphplot from GraphRecipes.jl to draw expression trees.

The best layout option is :tree but unfortunately the layout changes every time graphplot is called, even if the arguments are exactly the same.

Below you can see the result of calling graphplot on my graph twice. The arguments to graphplot are exactly the same both times. Each function invocation gives a different layout, sometimes dramatically so.

Is there a way to make this function print consistently across calls? If not then is there a better function to use to plot expression trees that will be consistent?