There's not really such a thing as "the" editor for a particular category. Rather than categories having editors, it's editors who have permissions to work in a set of categories. Some have just one category, some have several, and a group of around 200 ~(know as editalls) are allowed to edit anywhere.
The editors with direct permission in a category are listed at the bottom of the category page. (If you see "Volunteer to edit this category." instead, it means that there aren't any editors listed there.) However, anyone listed in a higher up category can also edit in all its sub-categories, and of course all the editall editors can edit there too.