De Dios led the redesign of C&IT, which was unveiled with the February 2010 issue.
Judges praised the art editor for her outstanding design on the monthly magazine and its brand extensions, which include Brand Book, Hot List 2010 and Stateside.
C&IT editor Yasmin Arrigo said: "We are all delighted that Susana’s expertise has been recognised by CWT at the Business Travel Journalism Awards."
C&IT's former senior reporter Leanne Bell also won the Meetings & Events Journalist of the Year award for her work at C&IT for the second consecutive year.
C&IT was recognised across six categories at the Haymarket Awards, held in May at Teddington Studios.