OK, looks like Kirk (and I) misunderstood your question. So the jpg and raw file show up b&w in PM but you want the raw to show colours instead?
The thing is, for speed (amongst other things) PM uses the embedded jpg in the raw file and this is b&w too. So you simply won't be able to get the original colours unless you use software to update the embedded jpg (which e.g. Lightroom does not do). If you're on a Mac another possibility would be to enable apple's raw rendering (set the preference, or press q in the preview window). This will then render the raw file in colour. Caveat 1: you must have a Mac and your camera must be supported by Apple's ImageIO, caveat 2: raw rendering will slow down your PM workflow.
An alternative solution: convert your raw files to dng (and have it embed a full size preview).