You might get lucky & find it in the Trash - otherwise iCloud, Time Machine or recovery software...
...though I wouldn't hold high hopes for that, my current iPhone backup folder contains 43,181 items, all with catchy, memorable names like
 0d0c1bdbcfa1d8f0cde357e7a4ab3db7783e26ff

Start by looking for it in Trash. If not, than a Time Machine backup. If not, try recovering it using a recovery software. The backup folder generally contain many files with cryptic names like  0d0c1bdbcfa1d8f0cde357e7a4ab3db7783e26ff and it may not be easy to deduce the correct one out of them.