the 3 isometry classes of irreducible [8,5,3]_3 codes are:

code no       1:
================
1 1 1 2 0 0 0 0
1 1 0 0 2 0 0 0
2 1 0 0 0 2 0 0
1 0 1 0 0 0 2 0
2 0 1 0 0 0 0 2
the automorphism group has order 12
and is strongly generated by the following 3 elements:
(
2 0 0 
0 1 0 
2 0 1 
, 
2 0 0 
1 1 0 
1 0 1 
, 
1 0 0 
1 0 2 
0 2 0 
)
acting on the columns of the generator matrix as follows (in order):
(3, 8)(5, 6), 
(2, 5)(3, 7), 
(2, 3, 6, 7, 5, 8)
orbits: { 1 }, { 2, 5, 8, 6, 7, 3 }, { 4 }

code no       2:
================
1 1 1 2 0 0 0 0
1 1 0 0 2 0 0 0
2 1 0 0 0 2 0 0
1 0 1 0 0 0 2 0
0 1 1 0 0 0 0 2
the automorphism group has order 8
and is strongly generated by the following 3 elements:
(
2 0 0 
0 2 0 
1 1 1 
, 
1 0 0 
0 2 0 
2 0 2 
, 
0 1 0 
1 0 0 
2 2 2 
)
acting on the columns of the generator matrix as follows (in order):
(3, 4)(7, 8), 
(3, 7)(4, 8)(5, 6), 
(1, 2)(3, 4)
orbits: { 1, 2 }, { 3, 4, 7, 8 }, { 5, 6 }

code no       3:
================
1 1 1 2 0 0 0 0
1 1 0 0 2 0 0 0
2 0 1 0 0 2 0 0
2 1 1 0 0 0 2 0
0 2 1 0 0 0 0 2
the automorphism group has order 48
and is strongly generated by the following 4 elements:
(
1 0 0 
2 2 0 
2 1 1 
, 
1 0 0 
2 0 1 
2 2 2 
, 
0 2 1 
2 2 0 
0 2 0 
, 
0 1 0 
0 0 2 
1 1 0 
)
acting on the columns of the generator matrix as follows (in order):
(2, 5)(3, 7)(4, 6), 
(2, 7, 6)(3, 5, 4), 
(1, 8)(2, 3, 6, 4, 7, 5), 
(1, 6, 7, 4, 8, 5, 3, 2)
orbits: { 1, 8, 2, 4, 5, 6, 3, 7 }