What do the aliens look like?

The San-Ti interface on Earth is embodied by an elegant woman (Sea Shimooka). But “we don’t look anything like this,” she admits. When Wade presses her to reveal what the San-Ti really look like, she bluntly replies, “You wouldn’t like it.”
The character doesn’t really have a name in the show, but she represents the alien “Sophons,” protons transformed into sentient computers able to draw power from higher dimensions. They’re an essential component of the plan to sabotage science and control perceptions of reality on Earth—so humanity will be appropriately vulnerable when the San-Ti arrive—as well as serving as an all-seeing, all-knowing surveillance system across the planet.
So what do the San-Ti actually look like? Is this a Childhood’s End situation or what?