San Francisco’s ambassadors of gypsy rock, Diego’s Umbrella, bring multicultural enthusiasm, humor and decadence to The Center for the Arts Saturday. Night after night, Diego’s Umbrella effortlessly blends marching drums, harmonized shredding and gang choruses with showmanship that has all the fire and unpredictability of youth, coupled with the refinement of years of experience on the road. The group’s uncanny gift for pleasing crowds, from standard clubs to huge festivals, such as High Sierra and Outside Lands, has earned it an ever-expanding following across the United States and Europe, and that connection with other cultures continues to inform the music. …