Run ROOT on google colab, working with python 3.10 [latest python version on Colab].

ROOT-Colab.sh

!wget https://github.com/MohamedElashri/ROOT/releases/download/ubuntu/root_v6.28.04_Ubuntu_20.04.zip
!unzip /content/root_v6.28.04_Ubuntu_20.04.zip
!apt-get install git dpkg-dev cmake g++ gcc binutils libx11-dev libxpm-dev libxft-dev libxext-dev tar gfortran subversion
!apt-get inatall libpython3.6-dev

# The following is needed because colab upgraded the openssl library
!wget http://archive.ubuntu.com/ubuntu/pool/main/o/openssl/libssl1.1_1.1.1f-1ubuntu2_amd64.deb
!sudo dpkg -i libssl1.1_1.1.1f-1ubuntu2_amd64.deb

import sys
sys.path.append("/content/root_build/")
sys.path.append("/content/root_build/bin/")
sys.path.append("/content/root_build/include/")
sys.path.append("/content/root_build/lib/")
import ctypes
ctypes.cdll.LoadLibrary('/content/root_build/lib//libCore.so')
ctypes.cdll.LoadLibrary('/content/root_build/lib//libThread.so')
ctypes.cdll.LoadLibrary('/content/root_build/lib//libTreePlayer.so')

import ROOT

h = ROOT.TH1F("gauss","Example histogram",100,-4,4)
h.FillRandom("gaus")
c = ROOT.TCanvas("myCanvasName","The Canvas Title",800,600)
h.Draw()
c.Draw()

Update: I built a ROOT version with python3.10 and updated the gist. You can use the method now without python3.6 virtual env trick. Example is provided here

I forgot to add that I updated the ROOT version to v6.28 instead of the old v6.14