B737 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Confusion; Situational Awareness
Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Incursion Taxiway
Air Traffic Control Issued New Clearance
Airport; Human Factors; Procedure
We were cleared to taxi from Gate B20 to Runway 34R via Taxiway Y; Y-2; C-1; D. The First Officer read back the clearance to Ground Control and I acknowledged the read back while looking at the airfield diagram and visualizing that we would taxi east on Y then join Y-2 which extends straight ahead of Y; then make a slight right turn onto C-1 at the end of Y2.  My mistake is that as I looked at the chart; I thought Y-2 was the east-west portion of the taxiway as it extended between two islands. In actuality; Taxiway Y-2 is a short north-south taxiway connecting taxiway W to taxiway C-1 and the ramp. As we approached the intersection; the First Officer did a good job and intervened by verbalizing that we were supposed to turn right. I was not mentally prepared for the turn and in the few seconds it took me to recognize my mistake; we missed the turn. Sacramento Ground Control noticed the mistake and re-cleared us to taxi via Y-1; W; D to Runway 34R. To me; the airfield diagram is misleading. I would prefer to see Taxiway Y-2 labeled vertically in the same direction as the taxiway orientation. The actual location of the letters on the current airfield diagram dated (date) led me to believe it runs east-west. For an example; see the LAX airport diagram regarding many of their north-south taxiways like D-7; D-8; D-9; etc.
B737 Captain reported confusion referencing an airport diagram that resulted in deviation from a taxi clearance.