How can I hide a sewer 'Candy Cane'?
Cutting it off is a bad idea. Aborting the "process of buying" that you're in might be worth considering if it bothers you that much. Relocating it significantly would probably require significantly relocating the septic system, which is very expensive - so you might consider it a "deal-breaker."

As for the location in the center of the yard, simply change your mindset from "I'm hiding this ugly thing I cannot believe is here" to "I'm putting a centerpiece in my lawn/yard." 

I'd go for a planting, myself, but seriously get out of the mindset (while retaining the function) of "just hide the darn thing" - put in a carefully laid out bed that has some shrubs that happen to hide it (paint it in camouflage colors, as well - white pipe does stand out.)