Here is what you are looking for;
30=R-SB, 15A=GN-Y, X=Y-VO, 50=GN-R, S=Y, 15=BL-R, 30I=R, 15I=BL-Y.

This is right out of the Volvo wiring schematics book for '98 S AND V70. From the looks of things you have a Y-W that does not show in the book and the book shows a GN-R. Don't know what to tell you other than to double check all of your wire colors. R-SB is Swede for Red/Black.

If your SRS light is on you may or may not have a wire in wrong. Deal with it is if you cycle the key with an SRS component disconnected it will log a code and turn on the light, but if you cycle the key with the ignition contact plate disconnected there is essentially no current going anywhere so the SRS control unit is not turned on and will not see a fault. Now that the vehicle is running and the light is on it is a moot point how the code got stored, fact is you need to have it cleared out. While the dealer can do it for you, any Volvo independent shop that is remotely worth a damn will have the necessary tools to reset your light and get you on the road. If you have any other questions about it just email me.

Oh, and whatever you do, don't pop that darn connector loose again. Don't feel too bad though, I did it once as a snot nosed trainnie too, but only once.

Good luck,
Mark