The air temperature needs to be above 60 degrees before you transplant a cactus, this is so that the plant will root faster into the new planting and it will cause less stress. Your cactus appears to be outside so you will want to be sure the temps. are going to stay above 60 before you do this. If you are moving it to a different location in the yard, pick a place that will have similar light, moisture, soil, protection from freezing and orient the cactus the same way that it is in the original planting to protect it from sunburn. Do not plant it any deeper than it is right now. Handle it carefully to protect yourself and so as not to bruise or damage the cactus during the move. Leather gloves work but I also like to use kitchen tongs since some of my cactuses have a bit more "bite" to them. Then just water it in. After that water only as needed, as it is important not to over water.