California vehicle code 12500 makes it illegal, and a misdemeanor, to drive without a valid license on any highway in California. A person cited for driving without a valid license in CA may be punished by probation, time in county jail, and fines of up to $1000 plus surcharges.
The good news is that a separate CA vehicle code 12951, discusses having your license in your possession. This VC states that a) The licensee shall have the valid driver's license issued to him or her in his or her immediate possession at all times when driving a motor vehicle upon a highway and b) The driver of a motor vehicle shall present his or her license for examination upon demand of a peace officer enforcing the provisions of this code.
However, any charge under this code shall be dismissed when the person charged produces in court a driver's license duly issued to that person and valid at the time of his or her arrest, except that upon a third or subsequent charge the court in its discretion may dismiss the charge.
When a temporary, interim, or duplicate driver's license is produced in court, the charge shall not be dismissed unless the court has been furnished proof by the Department of Motor Vehicles that the temporary, interim, or duplicate license was issued prior to the arrest, that the driving privilege and license had not been suspended or revoked, and that the person was eligible for the temporary, interim, or duplicate license.
From this information it appears that you should be able to get your ticket dismissed once you can show proof that you did have a valid driver's license, just not in your possession, at the time of your ticket. Call the court listed on your ticket to see how and where you must show proof and also if you will have any administrative fees to get the ticket dismissed.
You can read these California vehicle code subsections at the CA Department of Motor Vehicles site.