Something like:

We can observe that the lower right half of the parameters (below the diagonal with high C and gamma values) is characteristic of parameters that yields an overfitting model: the trainin score is very high but there is a wide gap.

The top and left parts of the parameter plots show underfitting models: the C and gamma values can individually or in conjunction constrain the model too much leading to low training scores (hence low validation scores too as validation scores are on average upper bounded by training scores).