GAP 4.8.9 installation with standard packages -- copy to your CoCalc project to get it
#g2 f1 6x6 1 0 0 0 1 1 0 0 1 0 1 0 -1 0 -1 -1 -1 0 -1 -1 -1 0 -1 -1 1 0 1 0 0 0 -1 0 -1 0 -1 -1 6x6 1 0 0 0 1 1 0 1 0 0 1 1 0 0 0 0 -1 -1 0 0 1 0 -1 -1 0 0 0 1 1 0 0 0 0 0 -2 -1 6x6 3 1 1 1 1 1 1 3 1 1 1 1 1 1 3 1 1 -1 1 1 1 3 1 -1 1 1 1 1 3 1 1 1 -1 -1 1 3 2^9 * 3^2 * 5 = 23040