To create a dialog for your own graph, ensure that the output of the graph is connected to the Output: utility node:

Then, copy this text and paste it into Edit > Graph Properties > Custom UI tab:
local __countdown = dotNetObject "Timer"
local __interval = __countdown.Interval = 350
local __tick = fn __tick s a dialog:(::execute (getFilenameFile pluginDefinitionFile)) =
if isKindOf dialog RolloutClass do (__countdown.Stop(); createDialog dialog)
local __event = dotNet.addEventHandler __countdown "Tick" __tick
local __start = __countdown.Start()
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It should now look similar to this:

Save the graph, Evaluate it (CTRL+E) and a dialog pop-up should appear - and that's it.
If you want to bind the dialog pop-up to a keyboard shortcut, put it to a button in a toolbar, menu or quadmenu, use the Macroscript Creator - you can copy the script path from the MCG Message Log after first Evaluating the graph , it is the file that ends with .ms