Why scalp color is different from translated area to non-transplanted area ?

If you have issues after your surgery, it is best to follow up with your doctor for a recheck. It is hard to diagnosis or tell what you may have or what issues you had during surgery (which may be a factor).

Normal to have the changes you are referring to. All surgery, no matter how good, leaves small scars that tend to be shiny compared to the surrounding skin. Also, the healed area will contract causing a bit of lifting of the transplanted tissue. This is normal and not usually visible at all to the casual observer.

It is not uncommon for patients to experience some temporary altered sensation in the recipient and donor areas after a hair transplant. This would usually settle within a month or two. There can be some subtle swelling within the skin of the recipient area that persists for several weeks after surgery and this could explain the appearance you describe. However, it would be wise to see you hair doctor so that your scalp can be properly examined. 

Usually the skin returns to its normal texture after the recipient sites area healed. If there was no hair present in this area, the skin is generally not as healthy as it is missing the normal support structures which will be rebuilt with the recipient grafts and then return to a normal appear scalp.