House paint
That brown colour the Electrolux Olympia One used looks like the same brown colour that was used years ago on houses. Go into a hardware store and see if you can find brown house paint in that same dark brown. Then contact the manufacturer - chances are, they either make it in a spray paint application for metal, OR they could direct you to another manufacturer/brand that does. Or, they might have a similar brown shade in spray paint that will do and be close enough.