This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
褨 combines the clothing radical 衤 with the phonetic component 差. The exact historical development and original meaning are uncertain.
The left side 衤 suggests clothing, and the right side 差 looks like a difference or discrepancy. Imagine a garment with an unusual, mismatched pattern that makes its meaning hard to pin down.
For サ, picture a sash (サ) tied around the mysterious garment: sash -> サ, and the sash is the only clear thing about this odd piece of clothing.