To view whitespace the setting is:
// Set to "none" to turn off drawing white space, "selection" to draw only the // white space within the selection, and "all" to draw all white space "draw_white_space": "selection",
You can see it if you go into Preferences->Settings Default. If you edit your user settings (Preferences->Settings – User) and add the line as per below, you should get what you want:
{ "color_scheme": "Packages/Color Scheme - Default/Slush & Poppies.tmTheme", "font_size": 10, "draw_white_space": "all" }
Remember the settings are JSON so no trailing commas.