How to plot sulci/gyri shading onto surface using nilearn

I’m plotting group average activation in grayordinate space onto a surface using nilearn’s plot_surf_stat_map. i used the templateflow surface as my background surface (i think this is correct if the data was produced using fmriprep with the flag --cifti-output 91k ). however, i can’t find the sulci/gyri shading .sulc.gii file on template flow to be able to shade my figure. does anyone know how to find this?