To configure Variation Swatches for WooCommerce Navigate to WordPress admin menu WooCommerce =>Settings =>Variation Gallery => General
1) Thumbnails Items Per row: Set how many items you want to show in per row
2) Thumbnails Gap: Set Thumbnail items gap in px
3) Gallery Width: Set Gallery area width in % for Large Devices then for others devices you can set in px if need to adjust you can increase or decries this width.
4) Gallery Bottom Gap: Set the bottom gap of the gallery
5 ) Reset Variation Gallery: Check to reset gallery after variation select