You can change the way TPC draws cross sections by editing the cross section (profile) settings. Cross sections are just profiles, after all. You will typically change the line type, thickness and color to differentiate cross sections.
TPC stores one set of cross section settings in the drawing and another with each traverse. See Drawing, Traverse and Object Settings for details.
Drawing, Traverse and Object Settings
Adding a Grid
Miscellaneous Profile Settings
Profiles
Editing Profile Settings
Cross Sections
Traverse Settings
Profile View
Professional