This is my method, posted on a different thread concerning the same subject:
I’m not at home right now, so I can’t include a screenie to show you what it looks like, but I’ve been using one of the diamond-shape note heads to approximate cues, and of course I add text to show which instrument is being cued. Even though I haven’t found a way to put the normal rest in to show it’s just a cue and shouldn’t be played, I find that it “intuits” quickly and easily from a player’s perspective.