Resnet plot saliency map

I would like to plot saliency map of Resnet 50 on my data after training.
I take on the layer4 the conv2 and I would like to plot.
Any suggestion on how can do? thanks in advance for any help

torch.Size([512, 512, 3, 3, 3])

Captum gives you an example of visualizing the saliency.