I made a post in June - Re: cerebro.plot / matplot quality. It was low priority so I finally found a solution and though I would share it with others. Place the following code in the notebooks that you would like higher quality plots:
%config InlineBackend.figure_format = 'svg'
here are all the options ('png') is the default:
‘png’, ‘retina’, ‘jpeg’, ‘svg’, ‘pdf’