Colo. Rev. Stat. § 24-60-1106
The provisions of sections 42-1-102 (81), 42-2-101 (1), and 42-2-102 (1)(d) and (1)(e), C.R.S., requiring residents of other states to secure an operator's license from this state shall not apply to persons licensed to drive by other states party to the driver license compact. This state shall require a resident to secure an operator's license from the department of revenue and to surrender any outstanding license to drive issued by another state; except that, if the laws of such other state require the person to be licensed to drive thereby in order to engage in such person's regular trade or profession, no license shall be issued by this state so long as such other license to drive is in force, nor shall this state issue any license to drive in contravention of the driver license compact.
C.R.S. § 24-60-1106