The liturgical funeral rites conclude with the Rite of Committal with Final Commendation at the time of burial or other disposition of the body. As noted, there is nothing to prevent devotional prayers for the deceased later, and a priest or deacon could be invited to lead them at the place of burial or entombment.
However, two rites are worth mention for consideration as possibilities.
First, if the gravesite had not been previously blessed for some reason, it could be. But this is somewhat to the side of the original question.
Second, and more to the point, it may also be permissible to use the Order for Visiting a Cemetery on All Souls Day, Memorial Day or on the anniversary of death or burial. This is found in the Book of Blessings. The instructions indicate it may be also adapted for use by individuals when they visit the grave of a relative or friend. It does draw upon several prayers in the Order of Christian Funeral (notably, n. 398). Since the instructions say “when,” they appear to expand the occasions of its use beyond those mentioned in the title of the Order.
The matter of the status of the deceased (Catholic, non Catholic, etc.) would need to be taken into consideration as noted above.
We would have to assume that the family of the deceased would be favorable to this, or that it would be something the deceased would have intended, or at least not expressly objected to (say, by a public and vehement rejection of the Catholic faith* rather than non practice). Even non Catholics and the non baptized are provided for in the Order of Christian Funerals in certain situations, and if those rites being the greater could be done, certainly the lesser could be provided upon legitimate request.
*Applying those possibilities in the case of one who was prohibited from Catholic funeral rites could be discussed with the local pastor. Devotional prayers can always be said though.
Peace.