Is it compulsory to make ghusl after giving ghusl to the deceased?

It is not compulsory for a person who gave ghusl to the deceased to have a ghusl. However it is mustahab (recommended) for a person to do so. (Shami 1/310-311)

There are many virtues enumerated in the Ahaadith for giving ghusl to the deceased.

Consider the following Ahaadith:

Sayyiduna ‘Ali (Radhiyallahu Anhu) narrates that Rasulullah (Sallallahu Alayhi wa Sallam) said, “Whoever washes a deceased person, shrouds him, preserves him (from decaying), carries him and offers the funeral prayer for him, and does not disclose what he has seen, he will emerge from his sins as on the day his mother bore him.” (Ibn Maajah 1462)

Sayyida ‘Aishah (Radhiyallahu Anhu) narrates that Rasulullah (Sallallahu Alayhi wa Sallam) said, “Whoever washes a deceased person, and he fulfills the trust and does not expose any defect, he will emerge from his sins as on the day his mother bore him.” (Musnad Ahmad 24881)

Sayyiduna Abu Umaamah (Radhiyallahu Anhu) narrates that the Prophet (Sallallahu Alayhi wa Sallam) said, “Whoever washes a deceased person and conceals any defect, Allaah Ta’ala will conceal his sins. Whoever shrouds him (the deceased), Allaah Ta’ala will adorn him with fine silk.” (Mu’jamul Kabeer 8077)

And Allah Ta’ala Knows Best