I can't tell for sure what she's cosplaying as, but my best guess is tanuki. The information might be in the translation of the text or commentary, so if you can find out please update the tags.

Examining kemono_friends animal_ears serafuku skirt tail, I think this is either tanuki or japanese badger. On this picture the neckwear if different from tanuki's, but it doesn't have badger's tied jacket.

I've asked on Twitter just in case.

worldendDominator said:

the neckwear if different from tanuki's

In post #3200718, as well, the fur collar is substituted by a towel or something.

Mitsumoto explains that in this conversation:

牛🐄C94 土曜日 東 テ26a @ tamagoshida0734
Replying to @ mitsumotocs

みつもとさんの描く尾根さん、首のモフモフをフェイスタオル括り付けてやっているの好きです。
5:32 AM - 27 Jul 2018

みつもと@C94土曜東I-03b @ mitsumotocs
Replying to @ tamagoshida0734

あー！気づいてもらえた！そうなんです…できる限りチープで雑なコスプレ感目指してるので…ありがとうございます☺️
5:35 AM - 27 Jul 2018