It is permissible to wipe off the water of Wudhu, but it is recommended to leave it to dry by itself. The Hadeeth narrated from the Prophet (SAWA) states: Who performs Wudhu and wipes its water will get one reward, and who performs Wudhu and does not wipe it will get thirty rewards. (Thawab Al-A'maal by al-Sadouq, page 32.)
Wassalam.