You can't see it directly tied to each guest, but you can figure it out based on the "your last x ratings have all been 5 star"... If your most recent person didn't leave you 5 stars, it won't have that message.
You can also count back the number of reviews to see which person (e.g. if your last 3 ratings were 5 star, the 4th review probably had the lower rating). That isn't as accurate as if you're catching them as soon as the review comes in (guests don't have to give stars in each category, so it's possible to miscount which person gave the lower-star review)